Dude, she had a one yr old, most likely didn't like the changes to her body; possibly felt completely undesirable. She had a fling, got some confidence back and now wants to make it work with the father of her baby. Either you want it to work or you don't. If you do want it to work, you would find a way to get over this. The fact that you seem to be full of righteous indignation says that you don't want this to work and this is an easy out.
Why were you looking in her recycle bin on the computer. It's one thing for her to lend you her computer, it's another for you to go through it. That's like spending the night at someones house and going through their drawers and cupboards. If you wouldn't do that, then there should be no reason why you couldn't just use the programs on the computer you needed to use and left the rest alone.
On the other hand, I don't know why she didn't empty the recycling bin before lending you her computer. Maybe she wanted to get caught...?
'People are never perfect but love can be. People waste time looking for the perfect lover rather than creating the perfect love' - Princess Leigh-Cheri from Still Life With Woodpecker.