He cheated.. What now? πŸ™πŸ½πŸ™„πŸ˜

I've been struggling with something for almost a year now and I know I can always come to <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a> for some judgment free adviceπŸ™πŸ½
Almost a year ago my boyfriend cheated on me. He had sex with the mother of his child TWICE. Him and I have known each other for decades but have only been together shy of 2 years.
I know he's truly sorry for hurting me and I believe everyone makes mistakes but I don't know how to move on. I'm forced to see her every time his daughter visits and the sight of her face makes my blood boil.Β 
Does anyone have advice for moving on or forgiving someone for cheating/ advice on rebuilding trust.Β