Struggling with partner - sexually

Ive been with the same guy for about 6 coming up to 7 years. We used to be really sexually active and couldnt keep our hands off eachother. Weve had a baby about a year ago and im just not interested and even if he tries to touch me im so just not in the mood/ uncomfortable. I dont understand whats wrong , why do i feel like this?? I love him and dont want him to leave but i dont know what to do. Someone please help