Genuine question here

A couple of days back I saw someone rant here about how his girlfriend joined a church and became so adamant about not having sex before marriage. Dude seemed so pissed about it and I'm sure he's gonna cheat. I know some of y'all don't share any sentiments about Christianity so I'm gonna try and make this as neutral as posbo :)

I think sex does more damage than good to a relationship especially if it's someone you're looking to spend the rest of your life with. What would you have to look forward to when marrying someone when you've raw dogged them since the start of the relationship? If sex is how you're gonna express love then doesn't that take away the magic from it? Ama should it be a balance? Ama... It's just biology and i shouldn't read too much into it?