emotionally draining

My husband and I haven't been trying very long, maybe 6 months, but it seems that every month that goes by it's becoming more and more emotionally draining, I get more discouraged and sad each month that passes. How am I supposed to let it go and not think about something I want so bad? My husband tells me that it will happen when it's supposed to, but it's hard to think that when you feel so disappointed. I don't know how I am supposed to just not think about it and be okay every month it doesn't happen.