I haven't seen this posted before so forgive me if it has been covered.
What made you look at your partner and say "Yeah, I could grow old with this person"?
For me it was within the first couple of months. I threw a couple of testing the water questions to see if he would just nod his head and agree with my (purposefully incorrect) statement, or if he would give me an actual answer. He politely disagreed with me and backed up his answer. That's when I really fell in love.
When I knew he meant what he said and said what he meant, that was it. No games, which was a breath of fresh air. I know I'd be getting married to this person because I appreciated the emotional stability and his consistency. I felt I could rely on him.
Oh, and cats liked him too.
Story time! Share yours!