Can You Be Friends Later On With A Cheating Ex?

I was with my partner for 5 years and during that time she suffered a mental breakdown. I stood by her since I did not want to leave her because of mental illness. However, her behavior got mentally abusive. She criticized everything I did, she played the push/pull game of wanting me when I wasn’t around but giving me the cold shoulder when I was present. I discovered an e-mail affair that went on for 4 months and they never met. I forgave her because I minimized her actions at the time. Eventually, she went out on dates with other guys and confessed to me that she cheated on me (after we broke up she told me this—when it wasn’t even necessary). My question is, there were obviously good times with this woman and I feel happy that we’re no longer together. Is is posstible for us to be friends in the future or even healthy? I’m not saying best friends but if I can see her once a year in a group of people where she cannot be abusive, would you think it’s ok? I am mentioning all the bad above and not the good….but there are times that I miss her terribly as we shared a lot of ups and downs in five years…...the bad eventually just got greater than the good. Can I still keep the good as just a friend from far away?