Maybe look at what you are gaining in the situation...rather than what you are losing and what she gets, both of which are really way beyond your control.
Letting go is really, really hard...sucks!...but is also vital to our serenity. I don't know about you, but I cannot put a price on serenity. I have tried and tried, in vain. Only becoming willing to surrender everything have I discovered a chance for true serenity for the first time in my life.