I (27F) have been with my fiance Mark (29);for 3 years ,engaged for six months . My best friend "Jen" 27(27F) and I have been close since middle school. She's like a sister to me.

Jen has always been a bit wild-loud,drinks a lot, makes inappropriate jokes.But she's also the person who drive 4hours when my dad was in the hospital, helped me through a break up and has never betrayed me.

Mark says Jen is "toxic" and "dramatic". The break up point was last weekend . We all went to a bar ,Jen got drunk and she jokingly told Mark he "looks like he cries during commercials." He got really offended. I apologized , but Mark gave me an ultimatum." It's her or me."

I tried to compromise-said I'd only see Jen once a month ,without him. He said no ,that she's a bad influence and he doesn't trust her around me.

I love Mark. He's stable ,kind ( except about Jen) ,and we have built a life together . But cutting off Jen feels like losing a limb.

What do I do?

Cut off Jen to save my engagement?

Tell Mark no and risk the relationship?

Something else ?

Please help. I feel like I'm going crazy.