He's gorgeous ! Why are you worried ? I would just quietly watch other women if I were you though - as he looks mature and therefore of interest to most ladies.
He loves you though, so just be happy
My first boyfriend looked older than he was, and the older ladies really liked him. He was 18 and looked 25-30 with big muscles too.
My second, I stayed with from age 17 and he was 18 and we married at 21. We've been together 22 years !
All that matters is that you've found someone special ! My poor Kenny lost his hair too...he's just turned 40, and it started to go from age 32.
Debra
Here are some pics of us :