weight gain and relations

me and my ex started dating when we were 15 we are now 20 and we’ve been on and off a few times but we always run back to each other. we’ve been dating for a year this time around. and when we got back together this time i had gained some weight. well about 40lbs. i’ve now lost all of it and am back to normal but i have stretch marks and a little loose skin. i can feel him constantly looking at them during any intimate time. it’s made me really self conscious because i know how much he hates it. when i was bigger he made so many comments about how ugly being fat made me and said thats why he left last time was because i was gaining weight. which i understand if he has a type but idk.

do yall have any advice to get rid of these stretch marks and skin or any advice on what kind of conversation i could have with him. i dont know what i need to do honestly. i just know how much i love him and how much i hate to see him not enjoying my body like he used to.