Moderately conservative sexual ethics

One question I might pose is whether long-term happiness in relationships depends in any way on our willingness and ability to make fidelity promises and to keep them, taking into consideration the kind of stable atmosphere for childrearing that provides. If the answer to this question is yes, then what I would call a moderately conservative sexual morality results. I say moderately conservative because it doesn't rule on questions like what people of clearly homosexual orientation ought to do about it, or whether committed couples should have sex before the actual wedding ceremony. A lot of traditional religious people want to go further than the moderately conservative position to a full-blown conservatism that limits sex strictly to marriage and forbids gay relationships, but I am inclined to think that the discussion of sexual ethics should proceed in a two-stage fashion: we first ask if moderate conservatism about sex behavior is true, then proceed to discuss whether or not the moderate conservative position should be extended to full-blown conservatism. Intuitively, I think moderate conservatism can be defended without religious premises, but the conservative position needs them.