I have been seeing this girl for like a year+. She has introduced me to all her friends and they are very cordial with me. She has this one friend who is her best friend and they share everything with each other. When my girl and I met each other we didn't know that we'd end up togather. We got drunk one day and were having an animated conversation about parties, during which my yet to be gf blurts out about her friend that she makes out with guys in parties. Months pass away and one day I meet her friend and her boyfriend and we go out to get drinks etc. Later we came back home and she starts telling me about how the bf asked her friend to marry her and bought a ring but she said no because she's quite young and doesn't want to be tied down right now before she gets her master since she wants to party one final time for 2 yrs in college. (They have been in a relationship for 3 yrs and there's an 8 yr age difference). So I chuckled and said "it's not as if she loves him, if she did she wouldn't cheat on him". My girlfriend got startled since she didn't remember telling me about her infedality. She just blurted out that her friend just went out once on a date and fucked a guy but that it's not what she does regularly. Now I was shocked since I was only referring to her kissing the guys not actually sucking their cock.

My gf pleaded with me not to judge her on that because she was a good friend of hers and was overall a nice girl and an awesome friend and if I told her bf she would know that it's my gf who leaked it since she's the only one in the know. Now after that I have hung out with that couple many times and the bf seems like a stand-up guy with good family background and seems quite morally upright. He is an accomplished doctor and also gives time at local food bank. Now the girl is overall a nice person with me and whenever we hang out she tries to be quite friendly and if I didn't know about cheating I would also give her rave reviews. The girl also told the bf (in front of me and my gf) that she doesn't want to marry right now and would like to have some fun in Masters and she wonders if she might like someone else in college so don't want to tie him down. If the bf wants he can break up with her. But her bf seems like doesn't get the msg. He seems to be in love. Now I have an awesome time hanging out with them. They are fun. But now the doctor has got a even more well paying job in a different city and he is again pressuring her to marry him. I usually don't care but I personally feel that the girl will keep on cheating on him and in the past it wasn't just the one time that she cheated that he doesn't know of. My gf I believe is concealing facts and trying to shield her friend. He seems like a nice guy and id hate for him to provide for a cheating hoe since the girl literally doesn't have 2 pennies to rub together. Although she is also a doctor. I so want to disclose her hoeing ways to the guy (although we aren't friends as such so I have no obligation). What are my options?Should I do it or not?Should I also dump my gf since she keeps company with such hoes?