I'd offer an idea like "How about going back to college? Is that something your partner would be okay with?" But I have the feeling that you are showing signs

I'd offer an idea like "How about going back to college? Is that something your partner would be okay with?" But I have the feeling that you are showing signs of depression. It removes all color from an otherwise colorful life. Get out of that situation as soon as possible, it is damaging your mental health. As for early retirement, check out the leanfire subreddit. I think your view on retirement could use a different perspective.