I know that it doesn’t feel this way right now and you are unlikely to believe me. However, affairs are not about love.
Love is wanting the best for the other person- which means by definition you would not start a relationship when you are not available to the other. You would not want their family to break up. You would not drop the other like a hot potato when the wife learns what has been happening.
Affairs are about escapism. They start often with two unhappy people who give each other validation. The instability and secrecy of the relationship leads to a push pull dynamic in which the highs are very high and the lows are very low. Each low takes each high to a higher place. It creates a chemical dependency in your brain that can create an addiction.
This feels like love, but what you will one day realize it was just a boot of bad decisions that gave you hope for the future that you were/are not feeling with your current situation.
The only way to help yourself is to try and produce more happy chemicals yourself. For me- I took up running. Any exercise/sunshine can help. There are foods you can eat that help your brain chemistry. Sometimes it takes medication, which sounds extreme but this is deeply related to the obsessive/compulsive type of issues.
Change the channel in your brain as much as possible. Stay busy. It’s hell. I have been there. But it’s not the dude, it’s the reliance on him to make you feel better/to save you. And I am not trying to be cruel here but the chances of him returning are very remote. Any contact you have will start the high/low cycle again.
Read the Wikipedia definition of limerance.
Also there are some great articles by dr. Frank Pittman on romantic infidelity. I remember being introduced to those articles and realizing that I was having a predictable psychological reaction to having an affair. It helped me see it wasn’t special.
You are in withdrawal. There is a great article posted to the top of this forum called Maia’s guide to withdrawal. It seems extreme but if you research it, you will see what I mean.
It’s really hard to realize that what you did didn’t have a higher meaning to it. But it does- just jot the one you are fixated on. The higher meaning and your new purpose is to learn to grow a life you do not want to escape from, which includes working out having thinking that you do not need to escape from. Your thoughts are not always true, and your emotions are based on your thoughts.