Arguing about ttc

My partner and I are 35 (I'm older) and 32 and having been trying to conceive for 14 months now. We are getting help from a fertility clinic but every month when it is my fertile window we are having massive arguements. It starts with my partner not understanding that they are 6 days or so that a woman is most fertile he thinks we did it at the start of my fertile window and that should be enough. Does anyone else have this issue with their partner? I have explained to him that a woman has 6 days, and 3 days before ovulation and the day before are the best time but he doesn't seem to understand why I am so frustrated when we don't have sex at the right time. He does have problems at times with performance and I know this is putting extra stress and anxiety on him which I feel awful about.

Is there any advice on how I can make it more romantic and less mechanical? I always make sure that when we aren't in the fertile window that our love making is stress free and fun but it's so hard not panicking and stressing that we haven't had enough sex or done it at the right time.

We both desperately want to get pregnant and start our family but we both didn't realise that it would be so exhausting and stressful on our relationship.