Betrayed by “fiancé”

HELP! I know what I need to do but actually doing it is the hard part. Maybe I’m looking for advise? Or some encouragement? Or someone to relate to...I’m not to sure honestly....

Let me give you a little back story. I have been with my BF 5 years engaged 1. TTC conceive for 2. He has a 7 year old little boy whom I love dearly. I have unexplained fertility issues and it’s really taken a toll on our relationship. I’m pretty sure he’s grown to hate me every time I get my period. It’s depressing. So anyways, baby momma and I have never gotten along we’ve said maybe 10 words to each. It’s alll been ugly. Well she recently got married in September to her sisters husbands son so technically her step nephew? But that’s besides the point! So months ago (i have saved for evidence) I found messages from her and my fiancé we argued whatever got past it. Well tonight I look through his phone and AGAIN!! So I confronted her threatening to tell her husband(which I wouldn’t, I’m not that type of person to ruin her life) even though she ruined mine AGAIN. At first she was a bitch and said I’m not scared of you do it then kinda sucked up and said she will delete him and do whatever she needs to do. 🙄I also found inappropriate videos, pictures, texts, and snaps from numerous different MARRIED women. He’s currently passed out drunk on my couch. Our home and car is in MY name only. I can’t afford it without him. I know I need to kick him out I know I do but to find the strength and courage to do it. I am so torn. My heart is literally hurting. I’m broken. I go to work tomorrow and plan on not talking to him until I get off at 6. Ignore all his calls and texts and then give him a piece of my mind come 6. But Im afraid I’m going to be cooled down and probably give into his stupid little “I’m sorry” and he will cry like always. I’m just so over it.

Oh and a little kicker to make this situation harder. My brother is married to his sister. So I’m sure it’ll start some family problems there which I don’t want to for my nephews sake😭😭😭

I don’t need any rude comments I’m already going through a lot right now!