He has a family but he’s leaving them for me!? Is it weird?

He has 3 kids and he is 50 years old, he has never been married. He was with his partner for 30 years but he lied to me in the beginning about being married so I had to back off, we work together in Nando’s. he’s the manager. I felt guilty at first because I was a nasty woman for considering being with an obese, middle aged man.. I’m not ashamed anymore however because I found out he wasn’t blushing and he picked up the courage to open up to his partner about me and his feelings, he is staying with me at the moment because she lost the plot, understandably because I’d be very angry too. I think she’s a lovely woman, it’s really hard. I’m 19. And this man is amazing, he is the most sweetest thing ever and I’m not going to lie I was jealous of them in the beginning because they were so close and he was always laughing with her but he laughs more with me now and i can tell he feels bad and we’re trying to overcome it. I doubt his partner will take him back after this and he doesn’t want to go back either. We have considered moving to Australia down the line, but we won’t go without resolving things.