Regarding the airline ticket - what airline? We had a similar situation a couple of years ago when we were taking DH, me, DD+BF, and DS+GF to Key West as graduation presents. I didn't think I would have any issues with cancellations as the relationships seemed very solid - DD & BF had been together 4 years and were talking marriage. But sure enough, 1 1/2 months before the trip, she tells me they are kind of breaking up and he will not be going. Great, I'm out over $200 for the airline ticket. I gave her a final deadline before I cancelled the ticket in case they reconciled. Nope.
This was on Jet Blue and at the time they gave me the cost of the ticket as a credit. I had a year to use the credit. We didn't have any trips planned, so I thought I would end up losing it anyway. But then we were invited to a wedding where the bride and groom were going on their honeymoon via Jet Blue. Even though they had already purchased their airfare, I was able to have them use my JB credit and have their credit card credited back the amount they had spent. It made for a very nice wedding present! There may be a change fee now.
But it would be worth asking your airline if there is any kind of credit you could get.
And I'm very sorry about the breakup. We eventually went through the same thing with DS and gf. It was not good.