WOW! So hard this is.

To have so much good stuff going on and yet not the main element: TRUST.
I am huge on trust and have always said if someone cheated on me that would be it for me.
But we are all different. And I think there are different circumstances.
If he told you he cheated on you then that shows he is not a chronic cheater.
If he was, he would probably not tell you so he would have the space to do it again.
If he told you then he must have felt really guilty for it.

Maybe it is a character flaw and he doesn’t want that to be the case and to rule his life.

But as you said, you are afraid that he will always be susceptible to situations that could put you both at risk in the relationship. If he seems to have the type ego that always needs stroking by others then I would be wary.
It would be hard to “share” my man emotionally with anyone else so I know I probably couldn’t deal with this.

I would say it boils down to how much you feel you love him. Can you live without him?
If so, you may want to give it some more time and space.
I know men want respect in a relationship and if he is constantly going to feel like you haven’t put this behind you then he might not be able to live with his actions either.

I would spent time in prayer, getting guidance on what to do and how to handle this.

I think you will know what to do after some time.

Best wishes to you! I know how painful this must be for you (and for him).