Help!

So me and my partner are engaged and will be together 5 years in September. We have a 8 nearly 9 month baby together. I found messages of him pretending to be me and sexually role playing with strangers he plays online games with 😩 he has also sent pics/videos of his manhood 🙄 I’ve pulled him up on his and he has now admitted to me that he cheated on me back in Feb and had oral sex with someone 😭 His needs aren’t being met so this has happened but he obviously didn’t understand the impact a baby has on your life - I’m absolutely heartbroken and now I don’t know what to do. His dad left him when he was young and I would never wish that on my baby but I just don’t know if I could ever trust him again 🤦🏻‍♀️ his needs won’t be met while we have a young child in our lives and he wants more babies 🤦🏻‍♀️