My partner and i had a healthy sex life up until i had a child and since ive had the child our sex life has been dismal which has made my sex drive crazy which is leaving me wondering what i have done wrong he tells me he is just tired but that never stopped him before i was pregnant.

him doing this is making me feel:
unattractive
resentment towards my son 1 in a month
like having sex with someone else

What Can I Do?