herpes... but from who?

I just found out that I have herpes. I've had three outbreaks that I know of but I can't remember when my first one occurred. My boyfriend now has only had sex with me, ever, but he has gotten blow jobs from two random girls in the past. My ex boyfriend had lots of sex with lots of girls before and during the time of our relationship. I don't know what to do because I need to figure out who I got it from. Need support 😔