I'm a little younger than you, but I just had this exact conversation with my now ex-boyfriend. Maybe I can give you some insight into what he's feeling?

No problems, no fighting, a lot of fun, but I found myself not wanting to be there for him physically. Not just sex, but hugs and kisses too. I had been feeling that way for a long time and I would distance myself when it became extreme to sort out my thoughts. He was the perfect boyfriend and I struggled for a long time about whether I was in love with him or if I was just desperately afraid of being alone.

Then I started to feel emotionally distant. I didn't feel excited about doing anything with him nor did I miss him when we were apart for some time. When I did see him, I would pick him apart in my head. I'd be getting slowly more and more annoyed with him, thinking if I could change these little things then I could love him more and this decision wouldn't be so difficult. I could just be with him and we'd grow up and get married and everything would be fine.

Those thoughts were so wrong of me. I'd clearly just fallen out of love. It took me a couple months after that to break up with him.

I felt like a horrible person, being so aloof when he was still putting a lot of effort into the relationship. When we broke up he asked if there was something he could do more or less of, such as going out to dinner more or giving me distance. It probably would have helped me feel better about the relationship in the short run, but I wouldn't be in love with him. I'd still resent him, when he didn't deserve to be resented.

So, afterwards, it felt like a huge mistake. I felt like I'd lost my best friend forever and seriously reevaluated my decision. I wondered if I didn't try hard enough, or if I'd mistaken my uncertainty in other parts of my life with uncertainty with him. I'd try to think about getting back together, but it didn't make me feel any better either. It felt like I was jeopardizing a relationship that I cared very much about (my relationship with my best friend) with a relationship I wanted to leave behind. Of course, they go hand in hand when your boyfriend is your best friend.

We are trying to be friends, but it is so different and the starkness of it can be very hurtful sometimes. For example, I'd called him to talk about a TV show we watch together and it felt very forced and latent with sadness and the awkward pauses were absolute murder. I still miss talking with him naturally, but hanging out with others helps. I don't think I am ready to be with him alone for long periods of time, but I would like to get to that point. I look forward to having a better relationship with him as his friend. I want to be there at his wedding. I want to know who his children are and all that jazz. I can't be his wife and I can't be the mother of his children, nor do I want to be, but I want to be there for him very badly. We may become more and more distant, we will be with other people that may have boundaries about the relationship between me and my ex, and I will accept that as it comes. But I don't wish to leave his life completely.

We also have a mutual friend group that is equally concerned about either of us and we are very lucky to have them. It takes a lot of effort to not ask for a relationship again because the loneliness is so crippling.

Something you may have to be strong about: don't take him back if he asks. I often reach a state of weakness where I have to hold myself back from calling him and beg for him back. It wouldn't change how I feel about him. I wouldn't magically fall in love with him again. I would just feel obligated to break up again and the second time around I'm sure it would be much nastier and resentful.

He sounds like he is being very mature about it. He doesn't want to hurt you, but he realizes you will be hurt. You also sound like you are handling this as well as you can. It takes a strong person to not be resentful of the end of such a long and mutually beneficial relationship. This is not a horrible thing, you are a much better person because of this man. You had a beautiful thing that a lot of people don't get to experience. It will take a long time to move on, but you have to focus on yourself. There's a whole half of you that was defined by this person alone and now you have to make it yours again. This is really vague advice, but it's all I've really got.

I'm on the opposite side that you are on right now. I hope what I've told you can help you rationalize how he's feeling and why he did what he did.