A break up is never easy for anyone......more so when you really cared about that person. The fact that he accepts it for what it is and acknowledges that he and she has changed shows a great deal of maturity. Yes he may still have some old unresolved issues, wither that is feelings or not is another matter. Maybe she was hurtful when they broke up and it bothers him that he hurt her? That is very common....to this day I still feel bad about girls I have broken up with.
The fact is he loves you......and what he had with his ex is in the past. Should she pop up and they start hanging out then you have something to worry about
The fact is the past needs to stay in the past......instead of rehashing what might have been with him move on and past this. The more you bring it to the surface the more time he has to dwell on it. Since he was the one to end things.......and still has no desire to move back with her there is no cause to believe he still has feelings for her.
We all wonder about ex's and if our current partner still remembers or misses the ex....that is natural. But do not allow a look on his face to cause a rift between you to.
Basically what he is telling you is, he regrets the things that he did. (He may have hurt her feelings and is regretting the choice of how he handled it) But that he is still glad that he did it. This is a mans simple way of saying he feels bad that he hurt the girl, but in the end he had to do it.
Men do not like to hurt women, that is why most come up with silly excuse or break up over the phone or in a letter. While we know it is wrong....it is also hard to deal with a heart broken women. As for your comment "I figured you would try to get back with someone is you believe she is right for you" This is not correct......men do not look at love the same way a women does. While he may felt she was the one, there was a reason why he felt they could not work though it.
Keep in mind as well that while he may be honest with you, he may be keeping certain things back. He may have cheated on her, or she may have cheated on him or maybe there was some aspect of the relationship he was unhappy with. She could have treated him disrespectfully XXXXX XXXXX does not wish to tell you about it. Men will be honest for the most part......unless they think that the truth could interfere with a new relationship. If he did cheat on her, he may simply not be willing to take the chance that you will see him with less respect.
In the end the reasons why do not matter.........he has said that he does not regret his choices and that he loves you. The more you ponder on how he felt years ago the less you can concentrate on your present relationships. The past is the past......let it stay there.
It is natural to feel a little jealous that he felt so strongly for someone before you........but you have to accept that this is just part of relationships. Unless of course you get with someone who has never had a relationship before.
In the end it sounds like he did care for her, but something about the relationship told him it was not going to work. Likely he knew he would be busy and she would come to resent him and it would end badly....maybe after marriage and children. It sounds like you have a pretty mature man on your hands that knows what he wants but also accepts reality.
The past is the past............and until you let it go this is going to be your problem not his. I know this is not what you want to hear, but the reality of it is what happened in the past has nothing to do with your relationship. If you allow this jealousy to take over and feel annoyed with him then in the end you will end up resenting him. Ending it may help........but if you do not learn to accept that people have pasts then no relationship is going to work. Most men have been in love before..........but if you hold that against them then having a relationship is not going to work. You have to let this go..........the easiest way of doing so is to stop thinking about it. When it pops into your head think of something else, the reality is the longer you dwell on it the more it is going to bother you.
Maybe she put the stress on him to marry and he was not ready. The most likely cause is he knew she wanted to get married and if she moved where he was she may push him more and if he was not ready he may have figured breaking it off was far easier then being pushed into a marriage he was not ready for. Keep in mind........if he was not ready to marry her then he may not have been completely in love with her. Sounds like he knew something was not right.........and make the best choice for him.
Have you ever heard that old song......"Thank God for unanswered Prayers"? I think it pertains to your situation very much. While he may have felt he was in love with her at the time..........had he not broke it off he would not now have you. Sounds like he is a lucky fellow that you care so much about him. Sometimes it better to just put things in the past and look forward to the future.