How do I tell him?

I'm ready to quit trying. We have been ttc for almost 7 months and yes I've already heard from way too many people that 7 months really isn't that long but to me it's been the longest 7 months of my life. And I want to quit trying. But my husband wants a baby and I don't know how to explain to him that I'm just emotionally done trying. We have 3 kids 2 from his previous marriage and my youngest from a previous relationship. He just wants one together and I really do understand but I'm the one tracking and charting and planning and I'm the one that can't get pregnant. Idk what to say to him anymore. I'm just tired of trying its too stressful for me.