OMG this guy

Okay so I posted last night but I deleted that because I didn't word my post right.

My wife(26f) and I(25m) have been married for 6 years and have 3 kids.

Last year we tried opening our marriage because my wife wanted to sleep with another man and told me if we didnt open she was going to cheat on me. Anyways the open part only lasted a couple weeks until we found out she was pregnant then we closed it again. However during that time she started talking to another man who I know but I've never talked to him. He stopped talking to her until a few months ago when my wife had our daughter.

At this point I thought things were getting better in our marriage but I guess not. She admitted to me that she was talking to him again because he flirts with her and makes her feel good. She also told me that he was her backup plan incase I decided I didnt want to be with her anymore. They stopped talking again for some period until a few weeks ago. I acted like it didn't bother me but inside it really did. I told her a few days ago that it did. She treated me like it didn't matter and told me I should just talk to another woman. She said I was just mad because I dont want her to have any man friends. That's not true. I want her to have friends. Yes it does make me jealous when its another male but I try to work through it. This is diffrent because of the things they talk about and how they almost slept together a year ago.

Well telling her how I felt didn't do anything because last night I read a message on her phone saying that she missed talking to him yesterday. Then again today they were talking about if she would get feelings for him after they had sex or not but having sex sounded good.

I don't know what to do at this point. Yes I admit our sex life isn't perfect with 3 kids, but I tried. I was rejected so many times that I gave up. It's clear she doesn't want me anymore but as a stay at home father I don't have the money to try and leave. I've considered just opening the marriage again so she can have what she wants, or it seems she will anyways soon enough anyway. I feel trapped.

She says she has post partum and feels like shit about herself and we can't afford for her to go to therapy. So I guess this is how she handles it.