When you made a decision to go with a "wait and see" approach, I think you made a wise decision. To have moved on as quickly as he did suggests that he was not all that deeply in love with you. You didn't feel secure about his love, and I think you were proven right.

Here is another angle. He may be a guy who just got to a point in his life where he really wants to be married. He may have been ready to get serious with the first girl who would give him the opportunity. He may be more "in love" with the idea of getting married than with either you or the other girl. Time will tell.

I think you have to respect that he has made a commitment to another person and let go of wishing that it was you. He's just not available. If you were to tell him that you loved him and he were to break his engagement, saying he really prefers you to this other person, wouldn't that make you feel pretty insecure about depending on him?

What do you think he means by wanting "to remain friends?" Don't read too much into that. It might mean he just doesn't want there to be ill will between you. That's fine, but it would not be appropriate for you and him to be seeing each other on a one-to-one basis. If he tries to call you or spend time with you, I wouldn't allow that if I were you. Just say that you wish him well, but that you both need to move on.