I'm going to ask my girlfriend's guy friend to respect boundaries
What boundaries isn't he respecting?
He had sex on my property.
It's crazy that he would do that!  He should be more respectful towards you and your property, and what he did was wildly inappropriate seeing as you're in a relationship with his friend.  I hope he understands not to do that again!
Yeah it made me angry at the time but I should be the only one who can.
If you own the property nobody has the right to use it as they see fit. I cant even imaging how upset you might be if you walked in on him in one of your spaces.