Insecurity in the bedroom...

I have never had confidence in the bedroom and I have never felt sexy. Part of it has to do with my weight I suppose and the other part has to do with the fact I have only ever had sex with one man My husband. (I didn't intend it that way) we had sex before marriage he just ended up being the man I married I suppose. The major thing is I know he has had sex with other women before me and he still 2 years into marriage refuses to talk about it or to tell me how to be better in the bedroom. I am very insecure especially after giving birth to our son 10 months ago that I am not attractive to him anymore. when we were first married and for the first year or so he wanted it all the time now I am lucky if he is minorly interested once a month or so.