Here's what you do - you start treating your partners with respect and leave until you have sorted your head out. Once you have, they may or may not want you back. I suspect not, but that's not for me to say.
Living with someone who is in thrall to someone else is horrible. You wonder why they are short with you, distracted, cold, all of that, because that's how they are. You might not think you are, but your mind and emotions are on some perfect prize. The person at home cannot compete with that so you don't bother with them, or their emotional needs.
Marriages aren't always destined to last forever, but whilst in one have the courtesy to respect your partner. They deserve someone who is in 100% committed to them. If that person isn't you, it doesn't make you a bad person, but you should step aside and let them find who ever it is. And they will. They won't sit and pine for you forever, they'll be initially lost and upset, but they'll move on.
Please listen to what I'm saying. So so many women on here are emotionally broken because their partners did what you are doing. Separation and divorce are hard, but when you throw a third party into the mix it hurts like you can't even begin to describe. Why were they better? Why? Why? Why????? It eats you up. It's so corrosive. It is no different for men. They are no tougher than women. They hurt too.
You once loved your DHs enough to marry them, have children with them, and commit to them. Remember that and be kind to them now. Don't tell yourself you are staying for them. You are staying for you, because it is the easy option.