Do we have any resources for marriage and sex?

Treating the other person as a person and not as a body is essential for love. Jesus explained to a 15-year-old boy, Emmanuel Segatashya (Rwanda) in 1982, the reason polygamy causes hurt to wives, as different spouses share the same husband. 

Book: The Boy Who Met Jesus: Segatashya Emmanuel of Kibeho by Ilibagiza, Immaculee 

Sex without commitment or birth control places a halt to the Holy Spirit in the relationship. Any use of sex without the intention of procreation is sinful lust. Even if we are heterosexually married, any sexual act that brings pleasure and release without the intention of procreation is sinful lust. This puts us all on the same playing field before God. Continence in married life is advised in Emmerich's visions. That's why, personally, I can't criticise any group. Natural Family Planning is the recommended choice by the Church to control pregnancy.

[Jesus speaks] So in spiritual life he who perfectly desires to be Mary must first be Martha, labouring physically to my praise. And he ought first to learn how to withstand the desires of the flesh and the temptation of the fiend and afterwards he may with deliberation ascend up the height of Mary. For he who is unproved and tempted, and he who has not overcome the lusts of his flesh, how may he continually heed and choose heavenly things? [Saint Bridget, 1360]

Some people would say, "I can't beat this addiction to sex, porn, and pleasure." If you really want to be in control, do this: Say a Rosary daily, and at the end, ask Mary to curb your urges; truly fast from Friday at 1 am to Saturday at 1 am on bread and water. If you want quicker results, also fast on Wednesdays; at 3 pm, say a daily prayer to Jesus for His suffering on the Cross, and ask Jesus to curb your urges (Mercy hour). Go to confession and be specific with the priest about where you failed. Go to Mass and take the Eucharist with a repentant heart for sins committed. If married, let the wife initiate and do not deny, but you must struggle for control and never initiate anything. Try to stay away from anything that will trigger your urges as much as possible. Do the above non-stop for a year, and continue if you want more control. You'll see your urges dissolve in time; it's subtle and effective, and the most beautiful thing is that you'll be at peace. Be grateful for God's help; keep doing this even if you are in control; praise God for his assistance. Or follow the twelve steps for addiction recovery from the book below.

Book: Walk a New Path: Forgiveness, Grieving, and the Twelve Steps by Sylvain Lavoie OMI;

Book: Love and Responsibility by John Paul, Pope, II

Book: Theology of the Body for Beginners: A Basic Introduction to Pope John Paul II's Sexual Revolution by West, Christopher

Book: First Comes Love: Finding Your Family in the Church and the Trinity by Hahn, Scott

The love high that lasts about 2 years after meeting your to-be wife or husband needs to be followed by her/his main love language for marriage to last ("words of affirmation," "gift-giving," "touch," "acts of service" or "quality time"); otherwise, your partner will start feeling distant from you. Gary Chapman explains it well in his famous book,

Book: 5 Love Languages Hardcover Special Edition by Gary Chapman

Prophetic revelations made to Venerable Mother Mariana de Jesus(1618-1645) by Our Lady Mary:

In the 20th Century... as for the Sacrament of Matrimony, which symbolizes the union of Christ with His Church, it will be attacked and profaned in the fullest sense of the word. Masonry, which will then be in power, will enact iniquitous laws with the objective of doing away with this Sacrament, making it easy for everyone to live in sin, encouraging the procreation of illegitimate children born without the blessing of the Church.

Let's define Masonic, its agenda is:

Marriage as a merely civil contract open to divorce at will, abortion, exclusion of religious education from public schools, exclusion of Church from the provision of social welfare and or control of charities.

It seems we are already there. Saint Thomas Aquinas said in 1250 about divorce,

The Old Law is described as "restraining the hand, not the will"... the New Law, which is the Law of love, is said to restrain the will... precepts of Our Lord are not contrary to the precepts of the Old Law. For what Our Lord commanded about a man not putting away his wife, is not contrary to what the Law prescribed. "For the Law did not say: 'Let him that wills, put his wife away': the contrary of which would be not to put her away. On the contrary, the Law was unwilling that a man should put away his wife, since it prescribed a delay, so that excessive eagerness for divorce might cease through being weakened during the writing of the bill. Hence Our Lord, in order to impress the fact that a wife ought not easily to be put away, allowed no exception save in the case of fornication."(Summa Theologica, Aquinas)

and,

Jerome: It is fornication alone which destroys the relationship of the wife; for when she has divided one flesh into two, and has separated herself by fornication from her husband, she is not to be retained, lest she should bring her husband also under the curse, which Scripture has spoken, "He that keepeth an adulteress is a fool and wicked." [Prov 18:23] For as he is cruel and unjust that puts away a chaste wife, so is he a fool and unjust that retains an unchaste; for in that he hides the guilt of his wife, he is an encourager of foulness...But if she do marry another, she is in the guilt of adultery; wherefore it follows, "And whoso marrieth her that is put away, committeth adultery."[Matt 5:32], giving her an opportunity of a second marriage...He says this to the terror of him that would take her to wife, for the adulteress would have no fear of disgrace.(Catena Aurea, Aquinas)

There is mercy in Church marriage annulments; questions and answers on this website. "[Jesus speaks] Those marriages that the supreme pontiffs permitted were ratified and to be upheld." (S. Bridget,1360).

Genetic researchers have identified several genes associated with Alzheimer's disease, but no gene to predict an individual's sexual behavior. So, if sexual behaviour is far from a body disposition, then it's to be concluded to be 100% psychological. If narcissistic parents can shape a kid's personality to be co-dependent and distrustful (https://www.youtube.com/watch?v=lY0Im1ePQu0), we may also strongly conclude that our childhood upbringing shapes our adult behavior. You know that when Pope Francis tried to voice this same logical conclusion, he was ostracised by the media. Also know that exorcists recommend psychological help for obsessions and addictions, and, as a last resort, substantial spiritual intervention.

A kid's relationship with his parents is dependent on their spiritual health,

They who look to wealth and not temper, to beauty and not faith, and require in a wife such endowments as are required in harlots, will not beget sons obedient to their parents or to God, but rebellious to both; that their children may be punishment of their ungodly wedlock.

Book: Catena Aurea by Saint Thomas Aquinas

How the human body reveals God is explained by John Paul II; for example,

In the language of the body, the conjugal act signifies not only love, but also potential fecundity. Therefore it cannot be deprived of its full and adequate significance by artificial means. In the conjugal act it is not licit to separate the unitive aspect from the procreative aspect, because both the one and the other pertain to the intimate truth of the conjugal act...It can be said that in the case of an artificial separation of these two aspects, a real bodily union is carried out in the conjugal act, but it does not correspond to the interior truth and to the dignity of personal communion: communion of persons. This communion demands that the language of the body be expressed reciprocally in the integral truth of its meaning. If this truth be lacking, one cannot speak either of the truth of self-mastery, or of the truth of the reciprocal gift and of the reciprocal acceptance of self on the part of the person. Such a violation of the interior order of conjugal union, which is rooted in the very order of the person, constitutes the essential evil of the contraceptive act.

Book: Theology of the Body: Human Love in the Divine Plan by John Paul II

So, let's analyse divorce, contraception, masturbation, abortions, and euthanasia in married life. The five biggest mistakes people make in marriage life:

Thinking about divorce? It is a selfish and narcissistic move on the part of the spouse to leave the relationship. Knowing that an extra-marital affair totally disregards the other spouse as a person, after divorce, the abandoned spouse will feel like a member of her body was severed, the heart will experience as physically bleeding, and anxiety will intensify for months, even years. If being married means working together with a person that has defects, through tough times, and looking for the other person's spiritual salvation, then considering divorce to start a relationship with someone else is the exact opposite.

Thinking about contraception? If pleasure without commitment is what one seeks in a married relationship, contraception is certainly the tool. It trivialises sex. Sex becomes a form of gluttony. It's like eating cheesecake for both pleasure and nourishment, then vomiting it up to avoid the nourishment part. Sex without contraception solidifies a relationship of commitment and responsibility for the other person and their family. It even feels physically different because contraception robs the person of the intention of sex.

Thinking about masturbation? Nothing gets a relationship off track faster than masturbation. It's like flying over a cliff by yourself; what seems like a pleasurable and relaxing view is actually a distortion of reality, just fiction. Reality can't measure up to the human imagination gone awry. We are slowly distancing away from our imperfect spouse, always searching outside of marriage for somebody more in tune with our fiction.  

Thinking about aborting a baby or euthanasia of a spouse? Sondra Abrahams, in 1970, was shown Heaven, Purgatory, and Hell after she was pronounced legally dead. She said:

Jesus showed me abortions. I saw billions of bloody torn bodies. Jesus started to cry. He said "You see, this is what mankind thinks of my Father's gift of life. They destroy it." After that He showed me euthanasia and said many would die in hospitals and nursing homes.

Miracle photo, Denver. What abortion does to Jesus.