Quote from Chockeh;596306:
Eh, I read that as: "Now that she doesn't have her memories back, she is like another woman."
They usually aren't /that/ different. Different toward the people they love, maybe, but only because they don't recognize them. It's very confusing and frustrating for the person with Alzheimer, which is why it's important for them to have a spouse or family member to ease the burden.
There's nothing wrong the dude being with some other chick if it makes him happy, but abandoning his wife for her is pretty cruel.