Girls. my bf is bi and wants to know if he can have a bf?

I think you should. As long as it's not romantic or a real relationship that could interfere with your relationship with him. What he says is true; there are some things only another guy could do for him and if it interferes with you and him, then you can tell him to stop. Just remember that if you choose to say no to him, he sounds like he really loves you and probably won't choose a phuck buddy over you. I'm sure that whatever you decide to reply to him, he will respect your decision.