So sorry for what you are going through.
Below is a link to an excellent article by Shirley Glass titled, 10 Questions to Ask Your Unfaithful Spouse:
For getting to the root of the affair and a better understanding behind the psychology of affairs, I strongly recommend you re-read the book, Not "Just Friends" by Shirley Glass
What does it mean if my WH says he felt "disgusted" and "crappy" with himself, instead of "content" and "satisfied."
It means he was racked with guilt. He knew the affair was wrong, he was hurting you deeply, risked destroying his marriage, and that he made vows in front of you and everyone that is close to him.
When a WS morally believes that infidelity is wrong, and yet they still cheat, they have a difficult time reconciling their actions with their core beliefs. Although the WS may become very disgusted by their behavior, the high and thrill of the affair can overrides their better sense of judgment. For some WS's, their guilt will haunt them for years to come.
Yet he also says he felt wanted, and felt needed by OWs attentions
This means some of his emotional needs were going unmet by the marriage; particularly the need for admiration or external validation. External validation is a strong motivator for having an affair (I know it was with my FWW). Your WH is telling you he has a strong need to be respected, praised and appreciated. He probably needs the compliments and affirmations to be said often.
What often happens in a long term relationship, the compliments start to drop off significantly, dissatisfaction starts to creep in, and the spouse may start to feel taken for granted. When someone new comes along and starts filling those emotional needs...a WS with poor personal boundaries will cheat. Their strong desire to end the perceived suffering, takes over. In other words, they become just plain selfish.