I'm sorry this is still affecting you so much PR, but not really surprised, it takes time to get past something and remaining in contact, well it's not going to happen.
It kind of sounds, from what you wrote, that you feel like you could drink, throw caution (and reasoning and etc etc) to the wind, pack your bags and drink your way over to London.
In doing that you would be making a decision to bypass the hard part of ending the first relationship before starting the next. You don't come across as that person, which may be why the drinking seems so attractive right now.
All I can think of is - play the tape forward. But perhaps backward first.
Although it was several years ago, remember how he treated you. Also remember that at the time you were together in person, you couldn't even speak the same language (ie: you didn't know him well). He has had your address for years. At any point he could have written a letter of explanation/apology, he chose not to.
Now you have his presentation of himself in chat, do you trust that? He was talking to you while he was with his wife, that's a red flag.
Now ffwd, you drink you hop on a plane and you join him.
He is someone you don't know well. It will end your marriage to your Husband. You will never live in the dream home you two built together, he will be devastated, you might be too.
If you are thinking of joining the ex, then there is a way to do it. Tell you Husband you are leaving him, quit your job, book your flight and go. If you don't want to do that then maybe it's time to cut contact? You know what his intentions are.