My fiances not attractive to me anymore

Kayla
So my Fiancé and I have been together 2 years and 2 months. 5 and a half months ago j gave birth to our handsome son, Oliver, who we both love dearly. 
Before I was pregnant we'd pretty much fuck whenever and very often. I loved him and still do so much, but after having Oli I don't feel the same towards my Fiancé. I love him so much but sex isn't important to me and I don't really care to do it and I don't find him attractive as much as I used to and I noticed this all happened after I had Oliver. I feel horrible. 
I bust my ass to be an awesome Mother and clean the house and I go to college but I don't feel up to par for him. His lingo lacks anyways (he's 23) but I mean I just don't know what to do. 
-Yes I'm on BC (the pill)