How to help not feeling sad at husband sisters house?

He wanted to go this weekend and I told him I rather stay home she has 2 kids and we personally have been doing fertility treatments and I know I get really sad so I didn’t want to be around that and so he basically made me come and her family is so cute and she has 2 awesome kids and I just feel so sad why can’t that be me. I’m not jealous I’m just sad. I want to go home. 😪 has anyone else felt this way? My husband says I don’t have a reason to be sad because “one day” we will have one but it’s not gaurenteed in our situation, I just want to cry.