You're saying you understand how it feels, and have empathy, yet you are only leaving him because you have realised that you've been strung along!
You're acting a bit like you're making a moral decision to leave and keep mentioning his wife as if you're trying to suddenly do the right thing... But if we had all said "Yes OP you crack on, he will definitely leave her eventually" you would have definitely cheerfully carried on sleeping with the poor woman's husband and waiting for the day he left for you and ripped her family apart.
The fact that you have been the wife in this situation makes it even WORSE that you're now the OW, not better, like you keep suggesting! You might have been hurt in the past, but that does not excuse or justify your disgraceful behaviour in willingly sleeping with a married man, so stop acting like it does.
You are an adult woman who knows what she is doing. You didn't "fall into" any situation. You willingly started sleeping with a married man and willingly continued to sleep with a married man. You are in the wrong, not the victim. I don't think you see that. You are still acting like the victim now! But you are the bad guy in this situation, you and this scumbag man. The only victim is the wife and his family, the only people not responsible are them.
You haven't owned your situation at all. This whole thread has been a) you hoping a married man will leave his wife for you and then b) a big pity party when you realised he won't.
The only way you have a chance to do the right thing is to walk away and take a long, hard look at yourself and your behavior. It will hurt, and you deserve that hurt, and you need to hurt to figure out that this is what happens when you sleep with a married man.
This was never going to end well for you. If he genuinely cared about you, he would have left months ago. And even if he did leave her for you, he'd only end up cheating on you somewhere down the line.
Affairs don't have happy ever afters. I have never, ever known of an affair to lead to anything but shame, and pain, and misery.
I try not to judge normally, but your attitude is really worrying because you seem to genuinely think you're the victim here. I'm sorry if this sounds harsh, but frankly I feel like you need to hear it or you're not going to snap out of this.