I have had a 15 year age difference and he was younger. It was great and he was most definitely what I needed at the time. Eventually we both matured and it ended.
I had just come out of the WTS. Emotionally I was probably a good match for him age-wise. I had a lot of growing up to do. He helped me enormously to do that growing up. That emotion growth went a lot faster for me than it did him. And eventually we were no longer a match and grew apart.
He was my life-line when I needed one the most. I think he is the one that I measure all others by. He was and still is the love of my life. And that is a scary thought.