S/he's saying that only because you forgive a person for something they did to you, it doesn't imply that the relationship between you two should remain the same. I can forgive my boyfriend for cheating on me while, at the same time, end the relationship. In theory, the Christian way to see it is to keep it in good terms and move on without passing more judgement or trying to get even. Once you say "I forgive you" to a person, it's your obligation to let the negative feelings go.
When Jesus forgave the prostitute, He also said "don't sin from now on" and, I suppose, she did so. That's the "proof" that the Church (or the current Catholic doctrine) demands of you: repent, ask for forgiveness, don't sin again. We don't know what's in Shoe's heart, so we don't know if she really has repented and she's moving on to a more mature lifestyle. But, if she indeed did so, she needs to prove that she wants to change AND change for real. Of course, this isn't our business but between her and God.
Now, with that being said, and I say this because we know what kind of person Shoe is, I personally think she's just adopting whoever her current guy's beliefs are and she's not being sincere. I could be wrong? Sure, but I don't think so. She's just pretending to be a good Christian girl until she gets bored of this guy or she gets bored of her. If she thinks she needs to do this to keep him around, then their relationship is failed from the start.