At 38 I was just out of a going-nowhere relationship, and convinced that was it for me. Three years later, I married a lovely man I met through friends and became a stepmother to three teenagers. Your life can change in ways you can't predict.
You don't have to travel, volunteer, write a novel or save the world in your endless 'spare time'. You do have to get your head around the fact that you still have plenty to do with your life, just because you're not following the same path as those around you. Like PPs, I think you post about this every couple of months and while the advice is always positive and varied, you seem very reluctant to reframe your own position.