I don't regret leaving him but regret the impact for our dcs, having 2 homes and split events but I know it is the best for them longterm. He was abusive so homelife would have been toxic.
The reasons for the split are important, such as abuse as you really have no other choice.
I also think if you know you did everything to try and fix things you won't have regrets.
Dating after a certain age is definitely more challenging but I think it is surprising how you meet new friends. A bad relationship doesn't allow you to grow which becomes apparent once you separate.