He was deceiving you for over 3 years? That says a lot about him.
This type of deception and loss takes a long time to recover from. Just know that time does heal. Remember that how you feel right now, is not how you will always feel. That feelings are not permanent.
Lots of self care and self love. Exercise is super important right now. It will help you release endorphins. Get a new hair style, go out with friends, and family. Volunteer. Travel. Do something you always wanted to do, but never did. These types of things are critical to building back your self esteem.
Dont rely on him for your self esteem or for validation. He is capable of lies, gaslighting, disloyalty. Hes not a good person and neither is OW.
Would you ever want to marry or start a life with someone that was cheating on his long term partner? To me that would be a huge red flag. I would run. He is not a prize.
