Men of reddit help me out please!

What happend when I slept with my best friend? Im a 20 yo female and slept with/fooled around with my bestfriend, 21 yo male. Is he still my bestfriend? He says he doesnt want a relationship and Im already in one. He wants me to stay with my bf because "he could never love me like my bf does" So does he love but doesnt want to be the cause of my break up? Or is he just using me for BJs?

Sidenote: he says the stuff about not being able to love me and then stays distant for a while and hes also is my bfs best friend.