Started playing when I was 10 or 11 and played for several hours a day through my teens and twenties, every day without fail. Joined a band at 18 and from then on was either practicing with a band or gigging several times a week. Got married at thirty, and that put an end to the band / playing out thing. Still, I practiced regularly and bought and sold tons of high end amps and guitars, which was fulfilling in its own way, and did a lot of songwriting and home recording. But somewhere around my mid forties, I just didn't find playing very interesting anymore (the fact that I had separated from my wife and was chasing pussy may have had something to do with that). Now at 55, I haven't played / practiced seriously in many years. I still have a few high end amps and guitars and am still tempted by FS ads (which is ridiculous), but I've seriously thought about just selling all my gear and maybe just keeping one acoustic.
It's a weird thing. My love of music and playing shaped my life. It was what filled me up, and it's sad that it doesn't do that for me anymore. I listen to tapes of gigs when I was in my twenties and realize that I pretty much peaked then. I can still play those same licks, but it no longer moves me to do so. Reading this thread I see I'm not alone. I wonder if a lack of progression has something to do with it, and specifically whether not having enough free time to truly advance your ability is at the heart of it. Life, kids for most of us make it no longer possible to spend hours a day advancing your craft (unless you're a pro and that's your job). I definitely still love listening to music every bit as much as I did when I was a teen.