am I wrong? 👀

So I recently found out my boyfriend of four years has a baby on the way by another women! In other words he CHEATED😡😡 so I I decided to let it go and forgive him because I don't want to hold any grudges and be at peace with the situation! So we still stay together because he's the co signer of my car and I don't have a great credit score to Refinance right now. We are still together for the sake of me and my car situation. So I know this sounds so stupid but I started to text some of my Ex's just because I was bored. So he went through my phone and read the messages. He said I betrayed him and I'm the reason for all this happening. I honestly don't think anything I'm doing is wrong I'm not pregnant by another man nor have I ever talked to another man until now. I don't know how to feel it's like he wants me to sit around and be faithful to him when all I want is for him to sign the car over to me and leave me alone. What do I do😕