Need some help.
My fiance's doesn't have many friends. She had 3 close friends in the past 2 years, a girl and a guy and me. The girl got a bf and stopped being available, my fiance and I got in a relationship, and the other guy who I could tell liked my fiance, kept being her only close friend out of the relationship. She'd text with him and talk with him and hang out with him all the time. Then when she got in her depression about 4 months ago she became distant from everyone.
A couple of weeks ago she got out of her depression and has tried to get social with all her friends again. Her and her guy close friend hit it off back again and were back to hanging out all the time (because he doesn't work and she doesn't work and I'm at work 5 days a week) and texting and calling and then finally he told her he loved her and has only loved her and hasn't got in a relationship with anyone for the past 2 years because she is the only girl out who challenges him and he gets along with so well.
And my fiance basically said let's talk about it and spent a day out talking with him all day. She told him that she wasn't interested in a relationship and was happy in the relationship with me but she wanted to stay friends and tried to get him to move on. He said he wouldn't move on, that he'd respect our relationship but he'd never give up on her until she's married and would wait for her.
Now in my mind, this is the point where you're like "uh, that makes me uncomfortable. Goodbye". But my fiance is so afraid of losing her only friend outside our relationship and was like "ok, cool. Great!" and since then they've been talking/texting like everyday while she tries to "cheer him up" because she felt bad he was depressed from the rejection and they've been hanging out in person and basically they're totally "best buddies". It was always uncomfortable before since it was obvious to everyone that he liked her and all the times they would hang out together people would be like "who is this? I thought you were in a relationship with bebpo" and they'd take lots of pictures together like couples. They joke with each other and tease with each other all day through texts and calls and I'll be sitting in bed with my fiance and she'll be texting with him and I'm like "that's not cool".
But she doesn't get it. She keeps insisting he's just a friend and she's only treating him like how she treats all her close friends, male or female. She jokes and teases with them and talks and calls and hangs out with them. I tell her it's different because he likes her a lot and sees her as more than a friend and it makes me really uncomfortable. She's always hanging out or talking with him and I brought up "emotional cheating" but she says it's not because he's just a friend. I go "hey, let's go see a movie tonight" and she's like "hey, can this guy come too?" and I'm like "no, that makes me uncomfortable" and then she gets mad at me like it's my fault. I've been avoiding any sort of group thing where he'd be there because seeing them together makes me feel really bad, like it's seeing her with her "other boyfriend" even if there's no physical anything between them.
I'm not sure what to do. Since she won't tell this guy to back off and since he's stated he won't move on, this is just going to keep happening. It's been like this for about a week or two now and it's been putting our relationship through a rough spot. I know she won't physically cheat on me as I trust her, but it hurts that she basically spends more time with him (through texting mainly) than with me and I feel like I'm missing the time/communication part of our relationship as she's going to him for it. I've said this to her but she just sort of avoids it with "it's not like that, I love you" stuff.
I feel like the only way to get rid of this feeling is for either him to back off, or me and my fiance to break up so she can just go shack up with this guy already and I can move on with my life. What are people supposed to do in situations like this?