Trust is the glue that holds two people together, it can be compromised sometimes yes because we are human, yes, but how we respond to those that we have compromised their trust is so important. Simple this like I am sorry, with deep remorse goes a long way. Making it up to you with action is also a good start.
Over the years I have learnt that we are all bruised human beings and we make mistakes but if it was an honest mistake, that relationship is work another try.
I figure that he has said sorry multiple times but his actions don't say so right? hence the multiple cheating.
In this case, I personally feel like you have to choose you. You have to make a choice that will make you feel good about yourself. Leave the heart out of this conversation for a moment because judging by your question, the heart is definitely ruling your relationship here.
Be honest with yourself and ask your younger self if you are really happy with where you are. the inner child will always set you free from whatever you are going through.
If you have any questions, or would like to chat, I am here to help. All the best, XOXO