Is it just a quick fuck or more ?

Just wanted to know opinions on friends with benefits. Basically me and this guy aren’t dating been friends a while but we fuck. Now, we aren’t dating cause we both aren’t ready. But that being said since we fuck so much during the week we came to the agreement that we must tell each other if we fucking other people. One of the main reasons for that is cause at times we go raw. I think it’s best to alert if you sticking it in someone else too. Tbh I’m only having sex with him. I talk to other guys but it doesn’t go past talking. Now as you can imagine I got feelings for the kid. This week he hasn’t been texting or calling. The times we would meet he has been cancelling. I logged into his fb account and saw a chat he has with this girl saying he can meet up today and she can spend the night she sent nude pics to him too. He hasn’t said anything to me yet about this girl that’s been coming and staying over. I do feel upset but should I mention it to him. Not that I logged into his fb but that I feel neglected and the lame ass excuses he trying to feed me I’m not buying..

I guess what I want to know is if you thing friends with benefits should be exclusive to two or is it something in which we all can fuck who we want without alerting the other one they also fucking someone else.