What is the best word to describe Alice's character in "How I Met My Husband"?

In the short story "How I Met My Husband," written by Alice Munro, the handsome pilot Chris Watters is already engaged to Alice Kelling when Edie meets and falls in love with him. 
When Edie first sees Alice, she describes her appearance negatively, thinking that there was "nothing in the least pretty or even young-looking about her." It's clear that Edie is being a bit petty and jealous when she says this, but it's also very clear that Chris is not as interested in Alice as Alice is in him. 
A good word to describe Alice would be unrelenting. We can tell that she has been following Chris around for a while, trying to keep him in one place, and she shows all spite and no empathy for Edie when she finds out that Chris, a grown man, "was intimate" with a girl as young as her.