I want a family but boyfriend is lost in a mid-life crisis

My partner is 48 and I'm 35.

- Dear Coleen

We don’t have children and enjoy a nice lifestyle. The problem is, he's really struggling with getting older, which is made worse because he works in an industry that’s run by young people for young people.He's started to act like a jerk - he flirts and eyes up other (younger) women, and it's a challenge to get him to take anything seriously. He does stupid things you can excuse when you're 21 not when you're pushing 50. He gets very drunk, he takes drugs and he’s dressing like an overgrown teenager.