I’m with Steve.

You absolutely should not be sleeping in the same bed as a cheat.

You’re enabling her behaviour.

She knows there’s zero consequences. She has zero respect for you.

There’s no motivation to save her marriage, because she knows she can bang another guy and has her soft safety net at home waiting, just in case she changes her mind. You might as well give her a big green traffic light and written permission.

My advice is this (don’t TELL her you’re going to do this or use it as a threat, just do it unannounced):

1. Next time she goes to OM’s house, change the locks
2. Text her that she’s disrespected your marriage and you’ll no longer accept it
3. Advise her she needs to find somewhere else to stay immediately
4. Tell her removalists will drop her belongings upon providing an address
5. Tell her if she has any questions, she needs to send them via your lawyer.

Women NEVER reconcile with men they don’t respect.

She will either
a) dump OM and get her sh*t together (and you’ll know it because she will beg for you back) or
b) she will choose to stay with OM - in which case she’s a piece of trash and you’re better off without her.

Time to rip this bandaid off.