I'd rather you be yourself with him. It's perfectly normal to feel the way you do about stretch marks, it's only natural for a woman to feel that way.
But everyone is different & obviously I am :) But again I'd always say and now out of personal experience I can strongly vouch not only for myself but also for those who think this way.
I have answered a few similar questions out here and here's one of those. Apologies I could probably have typed it in the amount of time spent on searching it lol but nevertheless read this cause it's a fact.