No confidence in the bedroom

Dr
I have no confidence in the bedroom, I can't confidently ask for sex (verbally or physically) and I can't perform any kind of sexual act with confidence even if my hubby is okay with it. I used to be confident I used to be be able to get what I want, but there are a number of reasons why I'm stuck in this place of timid fear.
One, my hubby doesn't have as high of a sex drive as me and he is more reserved so crazy experiences like sex in the car are a no go, he turns me down a lot. It didn't use to be that way but now that we're settled with each other he'd rather just have sex in or bed where it's easy. Over the years this has gotten to me and shaken my confidence. I'm afraid I'll be rejected yet again. And it hurts every time.
Two, im so afraid of being rejected, I can't just shake it off because I was emotionally and verbally abused by my first love. I can't help but to hear the things he would say that made me feel dumb anytime I tried to step out of my comfort zone.
And last but not least my body wasn't perfect to begin with, I'm flat chested with a small but cute butt and very thin and petite but my best feature was my flat tummy. But after having my daughter my skin is covered in deep stretch marks my tummy is badly pooched and I feel that my butt has lot it's perk. And my boobs just suck, always have. But I feel like I have nothing to be sexy with. No great features to advertise, and he hates lingerea. 
So I'm super self conscious an I can't do anything without feeling stupid, and when I get rejected it just cements my fears that I am looking/being as dumb as I feel.
What can I do to improve? My body I'm working but it's on pause as I'd like to finish having kids before working too hard to fix myself up. 
How do I boost my confidence and be the women I want to be? A wife my husband is proud of in the sheets? How can I feel better about myself? Help!