Is your b/f getting therapy for his porn addiction? Are you OK with being with someone who is addicted to porn? Would you marry someone who is an alcoholic?
Do yourself a favour and get some info on porn addiction and the consequences it holds - not only for the individual, but also for his partner and their relationship. You could google the words "Porn addiction" and also read a book titled "The Porn Trap" ..an excellent book on the subject by Wendy Maltz and Larry Maltz. You could also read Pamela Paul's book "Pornified".
To break an addiction to porn is very, very hard and could take years! People who are addicted to porn are very often not open and honest with their partners about their problem...so you wouldn't really know exactly how bad his problem is.
In my opinion you shouldn't marry this guy until you know for SURE his problem with porn is solved.
Are you OK with the fact that he's been with other men? Is this what you want for your future? How sure are you that he is not going to continue in his old ways?
I'm sorry..but sometimes it is necessary to be cruel to be kind. This person is going to cause you a lot of pain and sorrow.There is also a health risk involved for you if he doesn't practice safe sex when he is with another man!
My husband has been into porn for many years. Please..don't do this to yourself! Porn wrecks relationships and marriages.
Take care!
PS: My husband never watched gay porn in all those years when he was into porn. IMO your b/f has a problem and it's going to affect your relationship with him (sexually as well as emotionally)in a very negative way. Please get professional advice if you are not sure what to do.