Ah "solitude" this is a very familair word to me. Mine also told me that he had become a very "solitary person". I think the difference now is they come to a realization that he they aren't just "solitary" they are ALONE. He told me that he was afraid to give up his solitude and now he is afraid of growing old alone. I do think that the fact your husband seeks you out and that he can also tell you he loves you are very big things.
Yes my husband had 2 affairs (that I know of) during our marriage and 3 since, but this solitude that he talked about and was so afraid of losing, has kept him from being able to make a real connection. Sometimes I have even thought that because of his relationship with his Mother he really didn't like women. So he would use them. In fact on our very first joint counseling session our counselor had him pegged. She told me that ours would be his deepest emotional connection because she felt that he was that damaged. What was his response? Silence.
Would I have filed? Probably. Everyone has a breaking point. Besides, my kids needed to have their Mom back. Someone told me in the beginning that, "kids can survice and even thrive if they have at least 1 strong parent". How can our kids ever be truly happy unless they know that we are going to be ok?
In the beginning my very well meaning friends were trying to set me up constantly. It was uncomfortable and I wasn't ready. Heck if left up to me I might have never been ready. Sometimes things just happen and through business this man walked into my life more as a friend than as a romance. Maybe without any expectations or pressure, it felt different. I believe that everyone is brought into our life for a reason and that there are no accidents, so I try to be open to that. Even with everything that has happened, all of the pain and sadness, I have met the most amazing people throughout this, and I've learned something from everyone of them.
Keep your chin up and be still. You've obviously done something right if he is able to see (and voice) that he does know he loves you. So many people here would love to hear those words.