Our marriage may have reached the point of no return

I'm a man in my early 50s and I've been married for 25 years. My wife was my first proper love and we had a great relationship for many years but now we're different people.

- Dear Coleen

I've always been a positive person with a lot of energy for life but she has become insular and quite miserable. We're not close emotionally or physically at all any more. In fact, sex happens very rarely.

I've got used to it now but it makes me sad. I truly feel that our marriage has reached the point of no return and we're living different lives.

I have tried to talk to my wife about where our marriage is struggling but it always ends up in an argument and then things return to normal.

I think I have to leave because I'm not prepared to spend the rest of my life in a loveless, sexless relationship.