The Catholic Church does not have a meaningful set of rules about sex. They amount to "thou shalt not". The only ones allowed sexual activity are heterosexual married couples, and only if they pretend they are procreating. These rules are drawn up by those who are officially forbidden to have sex, so that they adhere to a theory.

The central dispute is between Catholics who believe the church should set the agenda for the world, and those who think the world set the agenda for the church. Those are ideals: in the real world, most Catholics will be a mixture of those orientations, but one predominates.

When it comes to sex, the ones who say that the world has nothing to say to the Church predominate. The problem is that just about everyone ignores the rules. 90% of married Catholics are using or have used contraceptives. The divorced and remarried often go to Communion. Gays are still having sex. Clerical celibacy is regularly more honored in the breach than the observance.