What does it mean if someone doesn’t congratulate you on your wedding?

I told my supervisors and some of my coworkers that I am getting married. Everyone was through the roof happy for me. Except one supervisor who knew I had a crush on him just a year ago and he got really excited. But eventually he noticed something about me that turned him off so he stopped pursuing me. He didn't congratulate me at first but sounded super incoherent like he was trying to rush me off the phone. Then later, he did manage to say "congrats" to me without any enthusiasm , as if he was supposed to say it rather than to say it with meaning.

When we met, he didn't seem to care , but I sensed that he was also a bit happy for me (body language wise) but never mentioned a thing about the upcoming wedding. But I thought he stopped pursuing me so its weird that he's not congratulating me.
What does it mean if someone doesn’t congratulate you on your wedding?
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