Cheating

So I just found out my husband is cheating on me. I’m having so many mixed emotions right now. The girl he tried to cheat on me with rejected his ass and she found me on social media to let me know that I deserve better because my husband wants to go outside our relationship. We have a one year old together and been together for almost 10 yrs now. Of course I want to leave his ass but we have so much together. Any idea on how I can bring up this conversation with him? Idk where to start or what to say because I’m so heartbroken.