Scheduled sex

Apologies for the length in advance...

Hubby and I have been trying to get pregnant for about 3 yrs now and we finally decided to see a specialist. The last couple of months I told my husband that I really want to try before we see a specialist which means scheduling sex. He hates scheduled sex because he thinks it's less romantic and less spontaneous. I definitely agree but in my mind if you want a baby so badly you do what you have to do to get one. We've literally only have sex once maybe twice during my fertile window. I've tried not to stress. One month I even stopped tracking everything thinking it would help. Didn't work. This month I went back to using opks and Pre-seed and again only had sex once 3 days before I ovulated. My fear is that we see a specialist and get prescribed medicine to take and I take them for nothing because we're not having sex as often as we should. How can I get him to understand that having sex more often has to happen to conceive? I feel like if it only took once it would have happened already.