I feel the same way, I'm early 50's. I realized that the reason people are always looking for friends is that at some point you realize your connections are only good to a point. With aging parents, children getting more independent, marital relationships growing stale, extended family members doing their own thing or growing apart, friends being busy or limited in what they can offer, it gets a little disappointing. You've done most of what there is to do by now. Hopefully there is more left to experience than hair dyes and wrinkle creams. With what time we do have left, we want to use it wisely and figure out our remaining priorities, a higher purpose, a passion, a lasting legacy, a once in a lifetime trip, a deeper connection, something to spark some creativity, or something to make life more exciting again. There are no milestones anymore like graduating, getting married, or having kids. We have to figure out what comes next. I think it's also harder for women. Men seem to get more distinguished with age, whereas women seem less valued by society as looks and hormones fade and that can be hard to deal with.