Love, When it that enough?

Life is complex and complicated. I surely don't understand many facets of it.  I recently was told by my boyfriend that he has a crush on another girl.  I've also been told that he's been forcing things with me and just doesn't feel "all that".
He says that we get along very well on some levels but he's not really feeling it on other levels.
I think that is bullshit.
I know how things are when they are bad.  This relationship is far from bad. It has been pretty good, Pretty damn good, if you ask me.  Sure, I'm not perfect, but neither is he. Lord knows he has his faults, too. Humans come with imperfections, which is part of what makes us interesting.  What I don't understand is how I can be in a relationship and feel that its one way, but that he doesn't share that feeling? How can I be so mistaken about my love?
Sure, new crushes are exciting and make hormones race. Crushes are not love, nor can they last. I've known this guy for over three years, and I had been getting in it deeper over time. He says he's been withdrawing lately.  I don't know if he's been withdrawing in order to devote more time to this crush, or that the withdrawing came first. I'm not sure I'll ever know.  I also know that over my 16 year marriage, I have had my share of crushes.  Meeting new people is exciting and feeling attractive to another person certainly has its appeal.  Despite these crushes, I never cheated on my marriage. Not while I was with my husband. Once I had made the decision to leave the marriage, then certainly I left it in all sense of the word.  Making a commitment to a person means sucking it up. It means having the crushes, but being man (or woman) enough not to act upon them.  Regardless of the length of a relationship, they will continue to appear and the devoted lover chooses, again and again, to quelsh them.
This totally sucks. TOTALLY.  I've lost this bit of comfort in my life that has certainly helped keep me sane.  I'm living this life that I'm only enduring because I know it will get better. I feel like I'm endlessly waiting for the damn construction to begin, and it keeps getting postponed. I want to not have to interact with my ex on a daily basis.  Being able to visit my boyfriend was an oasis in all this chaos. I feel I've lost my little island sanity and comfort.  I don't even know what will happen over time. I just know I'm seriously hurting now.