Hi,
I think that he could have just said something more concerning like “hey I think we should both see what’s going on with your weight” but the comment regarding he doesn’t know if he will feel the same sexual desire towards you is terrible. I cannot imagine someone, let alone my husband, saying something like that to me. If I were you, I would speak to him about how bad it made you feel. I would start considering moving on if it makes you feel bad. A man who really loves you will always make you feel beautiful no matter what.