Confront cheating bf or is it my PH

I keep on catching BV. I’ve had it 4 times already this year. I’m not too sure what is going on. I usually get it right after my period is done. Should I confront my bf and ask him if he’s cheating, or could it be my PH having a hard time balanced. My OB did say it can be because he does cum inside of me. But should I still ask I’m sure he’s not but would it hurt to ask??!