The age is right to be having a mid-life crisis. My former spouse had one which ultimately led to my departure - and I gather that he has remained stuck in (50s and hanging with 'friends' younger than our 31yr old daughter".

Did your partner experience some sort of crisis or upheaval that may have triggered his change in behaviour and demeanor? The change in my husband's behaviour came about as the result of a loss of his job and the two years that followed until he was successful obtaining a new one.

What is your husband's relationship with his existing friendship circle. With the loss of his job my partner basically lost most every social contact as so many were tied to his work. Thus he had an empty social vacuum.

Has he had a change in interest(s)? Enter the theatre for my husband and he quickly became consumed with that lifestyle. And this was the source for his new friendships and idiotic social behaviour. Suddenly he was hanging with those half his age - youth that had no responsibilities and the lifestyle of 'fun' and spontenaeity. Staying out frequently multiple nights a week went hand in hand with this.

What exactly is the nature of relationship with new friends? Is he at all looked up to? Has he become a mentor? My husband ad the opinion he was being worshipped. He had and has delusions of grandeur. Of course he would choose to hang out with these young people because his old friends would tell him to grow up.

Does he live two different lives?

I've given you a great deal to ponder. You need to nip this behaviour in the bud. If you are able to get him to couples' counselling please consider it. You may need to ask hard questions of yourself; namely, is this an enriching relationship still?

I truly hope for the best in your situation.