Love my man just wish he was younger

I'm 19 and my boyfriend is 42... I'm so madly in love with him and he feels the same for me. I just wish he was younger... not because I think he's old or looks old (he definitely looks no more than 35 and even that's pushing it) but I just get sooooo sad thinking if we live our full life expectancy he will die 20 years before me (the only reason why I wish he was younger)...and how heartbreaking is that? I think about death a lot... my own death and even the death of my mother, sisters etc... just because I know inevitably it will happen and it's almost like I am emotionally preparing myself for it? Personally, I'm not afraid of death..I don't welcome it but I'm not scared.. but when it comes to my love, the thought of him dying makes me close to throwing up. I can't even think about it deeply. Anyway.. are there any women on here who are significantly younger than their man and can feel my pain?