How to get over someone else’s relationship you thought would be “it,” the end game?

how-to-get-over-someone-else’s-relationship-you-thought-would-be-“it,”-the-end-game?

My older sister is recently separated. She’d known her husband since middle school, they were on and off. I should mention that she’s a little over a decade older than me, so I was not involved in their marriage growing up but knew they went through ups and downs to end up being the most lovely, charming pair you’d ever seen.

My sister was the breadwinner of the two, but her husband was receiving GI bill aid for school and I assume some other cost of living aid. These two are smart, accomplished individuals with hobbies and healthy social lives. I was going through hard times living with my dad and they offered to take me in. They literally took me in with open arms. I was struggling with anger issues and they were so patient with me. We had dinners at the table. Went to see movies. Talked about our days. Family things. When our brother was home from college it felt like even more of a family.

Before I moved they sat me down and told me they were breaking up. It boiled down to him wanting children while she didn’t. I love my sister so much and I respect her decision especially because I’m also childfree. But they miss each other so much and I can’t help but feel miserable. I never had a hope for my parents, but these two, they set the curve.

It took years for our dad to see my brother in law as a member of our family. I want them to get back together but I know it just won’t work out. How do I get over this relationship and be the most supportive sister? Is it still okay for me to talk to my brother in law?