Sex life sucks

I've been with my fiance 4 years and our sex life absolutely sucks. We've been trying so hard for a baby and sex has definitely become a chore. I am attracted to my fiance obviously and love him but I feel like we've just gotten so comfortable with each other there's just no physical intimacy anymore. I don't have much of a sex drive to begin with so it definitely doesn't help. I feel like there's no way to spice it up, it's just so blah. I don't know what I should do?