I think my wife is cheating.

I would never thought to find myself posting here.

It really sucks to be confused and not having anyone who can give you an advice.

I really need a mature opinion please.

I (M24) being married to my wife (F29) for almost 4 years.

We had a lot of arguments and almost separated twice. After the last conflict about a year ago. We decided to go back and always tell everything to each other. Anyways 7 month ago I decided to joint the Marines. And a few days ago I came back. To realized about so many thing.

We were always talking, and she was telling me “everything” of the everyday so did I.

She always full her mouth saying that she always tells me everything. And that she thinks I was keeping things from here.

She told me she wasn’t drinking going out or things like that Only work.

Today I was next to her and she got a text messege from her sister. She opened it next to me and I was able to see it. The text messege said. “What happened between you and my boyfriend the day we were drinking and I left for a few minutes”.

I instantly got mad. Because. That’s random and also she never told me about drinking with them or staying by herself with a guy I didn’t even know.

She immediately look at me and answer “nothing happened, and she wasn’t gone for that long”. After that she told me it was a while. I confront her again and she told me she was in the chair and he in the bed drinking. But while reading the text messege from her sister. I realized all of them were drinking in the bed. She left. And they stood in the bed. Then she told me we were sitting down. That’s it. She said.

I told her ask your sister why is she asking all this, why so random. She said it doesn’t matter. she won’t ask her what he said. Because it doesn’t matter.
After a while stepping Into the bathroom I get her texting her sister boyfriend saying. “Wtf did you text her that” we never did anything”

I left mad, because if she didn’t asked her sister because “it didn’t matter” they would she has to feel the need to ask her boyfriend

I came back after awhile and I just see the text messege of he saying. “I didn’t tell your sister that we did anything. I just told her the trust. I told her that we were drinking and laying down in the bed when she left”. My wife texted back we were sitting down not laying why you lie”

I think why she had the need to hid something like that from me if she was filling her mouth saying she tells me everything, also why the story changed so many times, or why would he lie about they being laying down over the chat, if he wasn’t aware of anybody else reading it. Or when she said. It wasn’t important and that was the reason why she didn’t asked her sister what her boyfriend said, then why texting him and ask why did he said so?.

I’m so confused, mad, frustrated we are about to get a house and I find this out. I don’t know if they hooked up or not. I wasn’t even thinking about my wife cheating.

But the only thing I know right now. Is that I can’t trust her, but also I love her.

I don’t know what to do. Any advice please.