C..
well, first of all sexy is a state of mind not a state of body.... so I would work on your self-image.
Sex is something that is a connection between two people. If you are emphasizing the body image part of it you are losing the intimacy part of it... and that's sad.
I don't want to only have sex with my husband when I'm at my best. I want to have sex with him to feel a connection, to share with him, to satisfy him and to allow him to satisfy me.
It sounds like you've lost that part of sex because you were so focused on getting (and staying) pregnant. That's natural, but it's a mindset you should change. Good sex can strengthen your bond as husband and wife which will, in turn, make you better parents... individually and as a parental team.
I like to start with communication. Share what you are feeling with your husband.... odds are he'll laugh at you. he doesn't care about your baby weight, your flabby whatever and your sleepless bags under your eyes. Let him see you as a woman...... and then maybe you'll start to see yourself as more than just a mom.