Advice on getting over resentment with my partner

My partner and I have been together for over 8 years. Over 5 years ago he cheated on me and we broke up for a couple of months. I was and still am extremely hurt about the situation/s that occurred during that time period. A few years forward, we now have a kid. My partner has put a lot of effort to gain my trust and to make this work. Although it's been years I have not been able to get over everything that happened. While I am with him I don't feel any resentment but love for him. When I am away from him I think about all of the things that happened and how I should've walked away for good. I would like to receive advice on how to get over this and move on.

We have a child and walking away now for something that happened years ago seems extreme.