No longer interested in sex!

I’m two months post partum and ever since I have birth I haven’t had much of an interest in sex. I don’t like being touched as much and I don’t like being kissed on as much anymore either. I feel horribly for my fiancé because I know he wants all of those things and sometimes I suck it up for him but I just spend all my time in mommy mode taking care of our daughter so it’s just hard to tune into sexy time anymore. I feel like if this continues my fiancé will leave me, Cheat or become miserable. HELP.