On the one hand, the Vatican places tremendous guilt on one of the most loving and pleasurable activities any human can engage in--apparently you're even supposed to think of God while you have sex: to do it for the sheer joy of it would be sinful.* And on the other hand, the Vatican has a policy that in order to enter its ranks, you must be celibate.
I speak of these two things as though they lie in the opposite hands, and that's what the Vatican wants us to think, but is it really so? I think not.
The Vatican, I believe, is like a doctor who makes his patients ill so that he can empty their pockets, and the type of illness the Vatican inflicts on its patients is guilt. When someone is guilty, he will do a great deal to redeem himself; such a person will almost become a slave if he must, and he'll certainly pay a great price. This price necessarily entails avoiding the act that caused the guilt, but in most cases something more is wanted. For one thing, very few people will feel that they've cleansed themselves if all they do is change their ways: the guilty want to make payment, not merely walk away. For another thing, their judge is often only too thrilled to oblige them.
In the case of the Vatican, you are asked not only to abstain from "unholy" sex acts; you are also asked to purge yourself of that and other types of "sin" by dedicating your life to Christ, who you supposedly harmed. You are to pray, you are to recruit, and you are to empty your pockets on the alter--these are all ways to purify yourself of your inherent wickedness, and the more guilty you feel, the more driven you'll be to do this. The Vatican is not a charity; the Vatican is a vast business enterprise that charges people for the illness it inflicts on them, and the more ill you are, the bigger the price you're expected to pay. If a Catholic's conscience were to be translated into a noise, it would sound like the ringing of a cash register.
It's unsurprising, then, to see that the ones who go the farthest to pay their debts to the Vatican--the priests, who have sacrificed most of their pleasures--are also the ones most prone to scandal. We think of them as holy men, but most of them are probably messed up in ways that their self-cruelty only hints at. Nor is it a surprise that they're prone to sexual problems, since other than being anti-Christian or simply alive, sexuality in any of its forms is the thing that puts you most in debt. Add to that the fact that the priesthood has a tailored remedy for this "sin"--celibacy--and you have a perfect honeypot for all manner of sexual outcasts.
*People who are in love with each other ultimately want to merge through a sexual act (and by sex we don't necessarily mean genital intercourse: all human interaction is sexual except where you're repulsed by someone; nor by love do we necessarily mean its most powerful form, romantic passion). Toward this end, a pair of lovers will try to seclude themselves not only from other humans but from existence in general; their goal is to get wrapped up in each other, and anything external to them, particularly a conscious being, will pull them away from this. It is possible for a couple to enjoy this situation rather than experience it as an obstacle, however, and this we call exhibitionism. The goal of exhibitionism is not to merge with your partner but for both of you to be absorbed into the witness. You can love the witness, and in fact you must if you're a exhibitionist, but you can only do so at the expense of your love for the person in front of you: completing yourself with A is not compatible with completing yourself with not-A.
Two resolutions to the situation of exhibitionism present themselves. One of them is to equate your lover and your audience, so that A and not-A become one. The other possibility is to revel in exhibitionism and seek, along with your lover, to become one with your audience. In the case of Catholicism, this would amount to calling your lover God or seeking to become God yourself, both of which are explicitly sacrilegious. Since the Catholic God is present not only before sexual intercourse but all forms of friendship, we see that this kind of God is a catch-22 for both romance and love in general: his presence, paired with the conditions under which doctrine permits you to experience it, forbid your affections to aim for the very culmination that they consist of seeking. If you love God, whether directly or through exhibitionism, you're trying to become a deity, and if you love people instead, you either do so with indifference to him or, equally sacrilegious, by considering him one of you. The God of Catholicism may be a god of love, but it's only a mockery of love.