They had just broken up.
Becoming separated doesn't need some weird or extravagant reasons. It isn't also the result habituation and of everyday hazards. Sometimes, being too good calm and understanding will throw you in a bitter unwanted solitude which you can't avoid.
Sometimes you should insist in your own egoistic demands. Some girls need you to persist on your unavoidable desires, i.e on having them in any situation!
It's hard to see that you are loosing someone just due to his/her high responsibility and dedication.
wish them to get together again
P.S: sorry for my weak writing skills. I'm trying to write in English in any situations and I nearly have no useful experience for it.