How about looking at it this way? Sometimes people do become unhappy with their lives and decide to make changes. It can happen to anyone, anytime.
If she can do it, so can you. Don't worry so much about how happy she may be, you can't know that. Even if she tells you she's happy, you won't know for sure.
Yours is the only happiness you can control.
Me 57/H 58 M36 S 2.5yrs R 12/13
Let me give up the need to know why things happen as they do. I will never know and constant wondering is constant suffering. Caroline Myss