This bird is a manipulative, unconscientious bitch. She indeed doesn't feel sorry; she just didn't want to be ratted out. And if she can have so much sex with guys she is not in a relationship with, why has she not had sex with you 3 months into a commitment?
She's just giving you the "loves" you line because she wants to possess you, not that she actually feels that way which is obvious in her despicable bird actions. Dump the ho.