What do you guys make of this?

Hi guys,
I was with someone for about 3 years and then he suddenly started to become distance such as almost never calling or just sending a text once every 2 days, which was very strange as I thought we were very close. I decided to break it off because I can feel that he wasn't as connected to me as before, but on that last day we met for the final time, he started crying in public like three times and saying that he doesn't understand why this is happening.
Within the past few months, he's been hanging out with a 40 year old single woman and they've travelled together twice only them, and he often goes out to have dinner and eat with her. He's 20 years old.
Why would a guy do something like this and even risk the relationship he has when its going so well just to instead want to spend time with a much older woman. I mean I get that the older woman can pay for his meals and take him travelling and exploring new places, but is that worth ending a perfectly good relationship over? What about physical closeness and connecting emotionally? Would a guy really choose to have someone to take him out and pay for his expenses over actually having a girlfriend who he can be there for him and show love and care for him, especially considering we've been together for a long while.