Holding back sex

Is it bad that everytime my ovulation week comes around, I don't wanna have sex with my bf? I get super emotional and don't even wanna be bothered by him. When I say emotional, I mean cry myself to sleep and can't even look at him. He knows how much I wanna be a mom. I feel like because he's a dad already, it's not top priority for him right now. We've been together for two years.