<human>: A few months ago I had a short (3 month) fling with a guy, lets call him K. 

Two weeks ago K got married.  

I didn't know he was engaged until after it ended. He told me he had a girlfriend after I moved, but didn't say anything about being engaged or that his wedding was so soon.  A few days ago I found out through a mutual friend (who didn't know he and I had been involved) that K got married.  I haven't talked to K since a week or so before his wedding (that I didn't know about at the time).  

In all honesty, I'm not upset or spiteful, I'm happy for him.  I just don't know if I should say something to him (like congratulations or "I didn't know you were engaged") or if I should just let it go and pretend like I don't know.

Can you succinctly summarize the text in 1-3 sentences?
<bot>: A guy I was with briefly got married two months after we ended (he was engaged while we were together and I didn't know). Should I acknowledge that I know he got married? Or let it go?