Oh. This isn't good....

Okay, so I need some advice...
So about a year ago I met this super sweet guy. He was in the Air Force stationed about an hour away from my home. We never had sex, but l guess you could say we were a thing. We went out a lot, he met all my friends, he was someone I could of seen myself with, but I just couldn't commit to him.
I recently found him on Facebook and come to find out that he's MARRIED and has a BABY.
I feel really bad because I mean we were dating, and the whole time he had a FAMILY!!!! and now I wonder if I should message his wife and tell her what happened, or just leave it in the past. I mean since then I found a super amazing man that I can truthfully say that I will marry. But it's weighing heavily on my conscious because I never wanted to be the 'other' woman.

Should I tell her or just leave it in the past???