ya...you can't force yourself to others...that doesn't work really....it may work temporary, but not in long term....
so, just be honest with him and tell him about your feelings and let it be....wait to see how things will go....
It looks like he has feelings for his ex and that's sad, but what can you do?
My ex boyfriend was like this, but I was the other woman....the one who was ex and he wanted me back....He told the new girl too...and I met the new girl....I felt horrible, because I knew how much my ex boyfriend loves me....and the reason we weren't together was just because I moved to California for a job and I didn't want to move back to Toronto....now you understand what I mean....He had her just as a backup....but he was honest with her....and he told her about me....we never got back togehter, just I met him whenever I'm back home....however, I don't have plan to see him anymore, because I don't want to mess around with his life....but I alwasy feel so bad for that girl....the last news was that he dumped her and went with another girl! so sad....I felt that girl has just forced herself to him...it was good temporary, but not in long term....
I don't say that your relationship is the same, but watch out, you dont' want to get hurt....let him to get over the ex first! and it should be his call....