Lower libido husband

My husband and I are both 31 and are trying for our first baby. Last cycle we had sex once during the fertility window and no pregnancy yet. He has a much lower sex drive than I do, typically once a week or every two weeks is our usual amount of sex. I’m having a hard time getting him on board with having sex every other day during the week of ovulation, he’s feeling pressured. I don’t want to feel like sex is a chore, even when we are going for a specific purpose other than enjoyment, but I also don’t want the discussion to turn him off entirely. Any suggestions?