I'm guessing you feel like she threw her happiness in your face somehow. I would be angry also. Its probably not even that she sent it to but that shes trying to prove to everyone she is. This entire process causes us to maintain control of our emotions and ourselves while doing whats right for our M, while they are off prancing in fairy tale land ignoring the huge piles of [censored] scattered on the landscape. Many of their own doing.
There are days I just want to let my emotions control me for once also and tell her off, but what would that really accomplish. We keep trucking forward through this shitstorm to a brighter future.
Accept what is, let go of what was, and have faith in what will be