Attraction is only partially physical.
I've been with my husband for 10 years (married for 6 of them) my weight has gone up and down I've been every size from a 4 to a 24, I'm about half way now between both of those sizes I'm currently a 14/16 depending on the brand. My husbands body has changed as well but not as drastically as mine. The attraction is still there, the spark is still there and the intimacy I'd say is amazing and has been at my thinnest and my heaviest.
It's not always physical sometimes it's much more than that. Bodies change, skin changes, weight changes, but the connection you have with a person has to be more than just physical or it will end once their bodies change...