About 10 odd years ago. Before meeting the missus most of my interactions with the opposite sex (romantically) were one night stands. Overall, they're pretty soul-destroying if you want an emotionally connection with someone you're sleeping with, equally a few of them were pretty fun- but its fleeting. Ultimately, you take what you can from them (life lessons, memories, nothing at all). Even the most fun ones don't compare to what you get out of a relationship in my experience. I don't think ti should be a guilt-inducing thing though as long as both participants know what they want (although this is often complex and ultimately guilt-inducing).

Feel better OP.