See the thing about religion is that I dont actually believe it represses sexuality, I dont believe any of them do, they just put it in its place and accord it an appropriate amount of attention.
Which to the absurdly dysfunctionally obsessed society in which we live appears like repression.
On the question of sexuality, procreation and marriage among the religious in the Christian and specifically Roman Catholic tradition, it has been overwritten and misunderstood and that misunderstanding has been further distorted across generations but originally a lot of the vows of celibacy and sexual abstainence (spelling) had close relationships to fidelity to religious orders, some of them military, all of them placing demands upon individuals which would have rendered them neglectful husbands and fathers, in the case of the military orders the Church did not want to be repeatedly petitioned by war widows and orphans or be complicit in the sorts of crisis occuring when men abandon home, hearth and kin to go adventuring in war torn climes. Similarly if your monastic order is raising a monastry, then engaging in scholarship or the work of scribes from morning to night, embarking on a long journey with no predetermined destination you'll be as good as a dead beat to any dependents.
A lot of real logistical and practical reasons there that have nothing to do with repressive hating on sex lives, pleasures of the flesh or anything of that kind.
Similarly there is the idea of a calling, now this isnt mystical or esoteric particularly, at least I dont think so, it doesnt need to be a celestial or cosmic shout out accompanied by dazzling light parting the clouds. Its simply that once you find your passion it becomes your preoccupation and your priorities change. No one would seriously imagine pouring disdain upon a grand prix race driver for hating on chess or ocean swims because their focus is driving fast cars the other occupations dont enter into their heads. This is what it seems like when I hear the rants about religious and sexuality for the Nth time.
Finally, there are religions which combine sexuality and spirituality, tantric sex for instance, the karma sutra is another example, even islam and christianity have their own pillow books, context and appropriate relationships is everything however and often the idea what monogamy, fidelity, commitment are preconditions or of important consideration to happy sexual relationships arent exclusive to religious sources. Arent exclusive to conservative sources either. Those sexual liberationists who throw those ideas out are witless and stuck in a moment of adolescent desperation and anxiety if you ask me.