My (33m) wife (34f) walked out on me and my daughter two years ago, now she returned and wants to be a family again

Two years ago, my wife pulled the classic "I'm going to buy some smokes" and just disappeared.
She suffered from depression and I did my best to take the load off her and help her get the help she needed. She would keep saying how she was sick of everything, even our daughter, and again I would give her space and try to accomodate every request.
Then she just disappeared, took some of her stuff and she was just gone. I had gone picking up out daughter at school after work and after we came home she was gone. Police was involved, but after three days she called her mother saying she was fine but wished for us to not look for her or contact her.
It was hard. Working, raising our daughter as a single father, trying to explain her why mom was gone and not knowing what to say when she asked if mommy would ever be back. At the same time I appreciated the strong bond I built with my daughter, and that helped a lot.
I never looked into or filed for divorce, but around last year' summer I met a woman, Jill, and we become started an on and off relationship. She knows all about my situation and although we are currently on break, she is still a big help and established a rapport with my daughter as an aunt figure.
I was thinking of getting the ball rolling for divorce when two weeks ago my wife returned. Completely apologetic, but she also seemed to have become a new person entirely: upbeat, propositive, almost with a "glow" to herself. She popped back in with a "Hey guys, what did I miss?" while after our initial shock, my daughter and I became diffident. In the last days my daughter has warmed up to her, but I didn't. She tried to initiate intimacy after two nights, but I told her I was not comfortable about it and asked her to move to the guest room, which she did saying she completely understands.
I asked her where she's been the last years, and she pretty much toured around the world (I don't even know with what money) and "found herself". I told her pretty bluntly that I was looking for divorce and that there's already someone else, she said she completely understands if I hate her now (which I don't) but maybe I can give her a chance to make it up to us.
I am torn. I still have feelings for her, and I'm glad my daughter got her mother back, but how can I trust her to not just walk out on us? What I am supposed to do with Jill? "Thanks for everything but my wife is back, so long and thanks for the fish?" What am I supposed to do now?
TL;dr Wife left without warning two years ago. Now she returned.


Source.