My wife hates & no interest on sex. Sex.

I m 28 years male. My wife is 26 years old.. we have a baby girl 3 years old.. And now she is pregnant 5 months.. Everything looks good right? But we had lot of problem in our sexual life.. She wants to have baby but don't want sex..She hates intercourse, no sex desire.. We just had intercourse 1 month before to get pregnant.. Only to have a baby. But she is healthy we didn't have any difficulty to get pregnant Remaining time in this 4 years, we just do make out & foreplay, no intercourse.. In that also she has lot of limitations, she don't want to have oral sex & no intercourse... Even for that also I need to beg her.. she don't have any desire & interest, she hates it.. when I call her, she got upset,She is doing all the things to get escape from that day sex.. Always she wants to postpone it..That leads to lot of fights between us.. That made me cry a lot & stress in my life.. Even she doesn't want to treat this issue medically.  Kindly advice medicines to turn on her feelings..