This is very sad, because most women think, that this is the best part of sleeping with each other... staying together for the night.
I can understand you need your space, i also have problems to sleep, when someone lies next to me, but if its someone you love, you can stand it for a night.
Next question: Do you tell the girls, you need your space and that you'll get up stright after "it" in advance or do you just do it? Cause if this happened to me, i'd think i've just been used and not needed anymore now... could be a point why you don't have long time relationships. I'd also feel cheated on, if i found out my boyfriend went to a nudie bar to watch other girls, even if he doesn't touch them or sleep with them - i assume you don't tell your girlfriends?
But you have to know yourself, i don't want to dictate you what you shall do with your life, i only want to give you a good hint from a womans point of view. Having a relationship means giving up all your ego and share your life with one person. Which also means running in danger of being hurt.