Should I be worried about my friend?

Besides trying to make her ex jealous she is probably trying to get some self esteem back. "They like me so why doesn't my husband? Its not unusual behavior but the highest group of new onset of STD's is in women of this age group who are getting a divorce. Maybe talking about STD's and maybe even birth control would be helpful rather than giving her your unwanted advice about her behavior. Try this when out to dinner or something. Gives you a safe environment and limits what you can talk about with no fights happening. When I went ththurhis my best friend gave me this same talk. Our booth was next to the bar and we looked up and saw these 23 year old boys looking down at us from their babar stool I told them "Yep, us older ladies like to!"