I reckon if you tell his wife exactly what happened, he would become totally available.
I don't think she actually got to the bottom of really finding out about you five years ago.
He will have denied it and said you were just a friend, crisis over, he's back in the home with his financials back on balance and you are still in the background for sex, that he may or may not be getting from his wife as she still hates him for having an affair which she never had absolute proof of.
Maybe, his initial separation sounds like she found out about an emotional connection with someone and he went for a while with all the bravado of a cheating git wanting his own way.
You were infatuated at this time and I hope you didn't leave your husband for him, as in your earlier post it sounds as though you are very angry at him for your possition after your divorce.
Infatution fades and if he had a long marriage it seems he really forgot what love means, it's so much more than sex and false promises and future faking.
Youv'e been had, you've been used whilst he had his mid life crisis, you are now useful because yes maybe his wife does not put out, yet he still chooses her and his children above you, he loves her and everything they shared over the years.
And her mental illness, I,m sure she was fine until he met you.
Both of you have acted very selfishly, you knew the score, his separation was not real, it happened because of you.
Tell his wife, she has a right to know the full facts.
I honestly don't know why you wouldn't.
5 years this woman has been lied to, that poor woman.
You have made a mockery out of this woman's life and you refuse to take any of the blame, only seeing your own losses.
He was never yours to fall in love with and I think you know this, this is why you do not wish to give him an ultimatum.