Sara, you tried everything you could. You reached that decision because after so many attempts he didn't change. You had no choice left. He was not respectful or remorseful, it's not possible to live with someone who is not treating you with respect or still make you responsible for his decision to be unfaithful. Until he has this kind of mind set there is not way of building/rebuilding something solid for the long term.
Now I am going to tell what I notice through the years of seeing a few men (mostly physicians) leaving their wives or divorcing them for much younger women, at first they were happy, very happy, they loved that new freedom until reality started to come down upon them. Most of them if they left their wives for someone else, got dumped after a few months or left their new relationship because the la la land disappeared. Also what a wife is willing to accept because of their common past, a new "woman" might not be so eager to do so. And having the kids for a few days by yourself is totally different from a few hours with a fridge full of already made meals, laundry done, homework done...
Usually it takes them between 1 year and 3 years to realize what they had and how stupid they were. Real guilt and regrets come slowly, they need to live through the negative consequences of their actions and the harsh reality of their new daily life to become aware of the mess they created.
A few went back to their wives if they were still "available" and willing to give them another chance under certain conditions, some discovered that their spots were taken and they were not missed. And what happened to their former wives, after sadness and grief they became quite happy with their new life, because they didn't have to deal with that constant negativity and walking on eggshells anymore.
Sara, focus on getting the better deal you can on the process you are engaged in, you might get divorced or you might not, life is something always changing but don't settle for less than you deserved. We respect courage and chase what is worthy not the opposite.
One day at a time, don't give up and keep up your boundaries, very tough but that's the best you can do for the long term.
((hugs)))
Me 52+ WH 57+ Married 20 + Piecing since 2016 (ready to give up...)