It sounds like they are still very much married and not just in name. With him continuing to declare all this love for you and ask you to wait, well, it’s very cruel. Not just to you, but to his wife and children because he’s lying and cheating and keeping you as this secret on the back burner. That prevents his wife from moving on and perhaps finding someone one day who truly does love and respect her, his kids from having parents who are happy and settled together, and of course keeping you in limbo for half a decade. Also preventing you from finding someone who could actually be good for you.
After everything you went through before with your ex husband as well! He must know about that but has kept you hanging on, lying to you, lying to her - it’s cruel.
Peope like him give it this grand romantic ‘noble’ narrative - oh we are meant to be, written in the stars but I must do the ‘right thing’ for my kids and my wife blah blah etc. But doing the right thing would have meant separating from her and being a decent co-parent or if he was determined to stay to not keep you hanging on. It’s not ‘the one’, and if you keep hanging onto a memory of a ‘perfect’ time you won’t ever move into a happier phase of your life. Maybe it was an amazing time but that time is gone and it isn’t coming back. Even if he left tomorrow how can you ever heal and have this ‘perfect’ relationship with a man who did this to you for so long, and to her and to his children?
How can you possibly believe he is ‘the one’? How can a man who does this to you over and over again ever be your perfect man, the one meant to be with you? Even if ‘the one’ existed, this is not it.
You CAN start again because right now there is nothing to lose so really you already have started again. It’s hard to let go of so many years of yearning and I imagine fantasising about how amazing your life would be together if he just left. But you must let go of that idea, get rid of this notion he is the only man for you.
You’re not old OP, there’s a lot of life left for you. Is this how you want to spend it?