Husband feels used

We have been actively trying to have a baby with no success. I told him we'll have sex every night this time just to make sure I cover when I ovulate. He didn't object to it when we discussed it. We've done it for a week and he's not happy about doing it every night. I've used opk and still feel obligated to have sex that day. I feel like I want to have a baby more then he does. I take charge and he doesn't need to put in all the effort but it's obviously not enjoyable for him anymore. He said I'm just using him for his sperm. He asked, what if it doesn't happen this month, I said maybe you can take some zinc, it could improve the quality of your sperm and he got really offended about it. Any suggestions or advice on how I can fix this?