Cheating?

So here is my story. Would like to hear thoughts after please.

About 4 years ago I met the women I'm with now. She has a shady past of sleeping with alot of guys just because. That's what she told me. I'm not one to judge though.we clicked just right. So I decided to give it a go even though what she told me and I've been cheated on throughout all my relationships. Well, around 3 years now she started talking to this guy she knew through texting. I was okay with that. But then it started becoming more and more. From the time she woke up till the time we went to bed. Laughing and giggling right beside me. I caught part of a mesaage saying something about her faking something. But then when I went to see the messages they were all gone. Everyday they would be gone after talking to him. So from learning to look for signs from my past. I brought it up. And seemed like she came up with excuses as to why her messages disappeared. She had told me once that she has alot of guy friends as well. I asked her if she had anyone on her facebook, snapchat or instagram that she has just randomly slept with. She told me no. Anyways. I ended up pulling away from her. For a long time. Well the girl I'm with is a bit open minded and into some things she was trying to get me to be into. Which was fine. I'm open to almost anything. We had created a private instagram just for the 2 of us. Well 2 and half years later or so. I find some dude she knows on it that is also on her facebook. So I questioned it. She said she didnt even realize he was. But as far as I knew, if its private, you have to invite someone to it, and accept them. And what you ha e to understand is that she is very thorough. And pays close attention to detail. I asked how she met him. She tells me they only met once, and have been chatting ever since and friends. But when asked to delete him cause I didnt feel comfortable she lost it. Anyways, needless to say that didnt get solved. Then sometime later. Because I pulled away from her. She did the same and because emotionally detached from me. Then throughout the hole month of march, her and this guy she had on facebook were trading emotional post back and forth like 6 , 7 times a day and commenting on all of them. Now were we live is a complex. And we have been living here for 3 and half years. This guy drives a older red dodge pickup that is similar to my neighbours truck. Except this guys truck is raised. Well I've never seen his truck here before. And it just so happens to be in my parking lot one day when I came home from work to get something. When I entered the house, she was acting kinda shady so I had a gut feeling something was wrong. So I checked the rooms except for one. Then 2 days later she shows me a post this guy took after midnight one night saying he found a truck just like his. In it was my truck, his truck and my neighbours. She had commented on saying oh is that your truck, that's ours too. And another car. Well the posting continued between them. So I looked into this photo a bit more and I see what looks like her reflections in the doors and such. And something I didnt mention. Is that I have third stage copd, and mild sleep apena so I sleep like a rock and hear almost nothing. She also dont like the cold weather but one of the reflections looks like her in a tank top. Then she found out I was looking into it. And she finally tells me well you may find out I slept with him back in 2012 cause I was going through a rough spot and it was convenient. Well, she had been talking to him through facebook messenger as well. But deleting certain parts of the convos. Also she like adrenlene rushes. I feel like she brought this guy in our house to sleep with him well I was sleeping. Any thoughts towards this would be great. Thank you