My husband isn't committed

So, my husband and I have been trying to get pregnant for almost a year. I think we haven't succeeded because we aren't having sex enough during my fertile time. He's been really good all week about having sex but has lost his steam...we needed to have sex tonight because my ovulation test came up positive. Instead he said he wasn't in the mood and we had a big fight. We always fight about this. I almost want to give up. I'm the one who has to track my temp everyday and check for CM and pee on freaking sticks. All he has to do is have sex. Geeze tough life. Can anyone relate? I need advice.