Thanks BirdDancer, Christina and WC for giving me some tips on my difficulties with my friend. It is about boundary crossing.

What made me the most uncomfortable was his talking about his wife's small breasts and how she had a body image problem and would benefit by going to the nudist event with him. He went on and on about her breasts. This is what creeped me out the most. I felt it was also an invasion of her privacy. He also complained about her giving him the silent treatment for days on end and dropping out of the relationship. They have been married for close to 50 years.

I know I need to say something to him next time i see him if I want to maintain the friendship. I don't think I will text him anything, it is better to say it in person but I am not sure what to say.