relationships

Jessie
So my boyfriend and I have been together for over six months now, and he's known the entire time that I'm bisexual but he just recently told me that he wants to experiment a little. So he asked me if it would bother me if he went and spent the night with another guy to "get his gay on" to which I told him that he was open to do what he wanted. I told him that it didn't bother me.  Although now I question if that's going to change our relationship any. I've talked to him a lot about it and he said that he'd cancel his plans but I don't want to make him do that. I still want him to figure himself out. Im just terrified that something will change and things won't go back to the way they are now.   He's the best guy I've ever been with and I don't want to lose him. He's the reason I'm still breathing. 
I just need some advice on what I could do