It's good that you guys had a heart to heart...
To think that I rejected something that today I long for makes me feel so bad and that is one of the reasons he prob went elsewhere to feel loved and wanted.
This thinking worries me. What stopped him from telling you he felt this way before he went out and had an affair? He needs to question this about himself. Why did he tell himself "no" when it came to expressing his feelings to you, but "yes" to entering in an affair with someone else? Surely he cannot expect you to be a mindreader.
It is a good thing that he was able to say how he felt and that he would like more affection with you. At the same time, can he acknowledge or understand what was making you busy those other times? Was it work, dealing with kids, doing things around the house, (ETA: read your profile) wedding preparations since you two were engaged? Perhaps you had a reason you were busy as well. It sounds like it really helps that you guys are talking. But please don't blame your marriage issues for his decision to have an affair. He had other choices.
He told me all about the OW and even though it kills me to say she sounds nice.
It's good that he told you about the OW, hopefully answering all your questions. Is he still carrying fond memories of her though? In that case, it sounds like he needs to be more proactive, instead of coasting along, to see the A for what it really was. The OW might not have known he was married - so there's that - but he did. Why does he carry positive memories of his betrayal to you? Hopefully in time, he won't.
I hope he can look back at his marriage history and appreciate all the things you WERE and WERE DOING that made your marriage special. Pre-A. The things that maybe he didn't appreciate before that were always there.
Hope you all will keep talking. Sounds like healing.