[Brandye]

And, now, an alternative view. You are showing signs of jealousy. Bad, bad. She is also not letting go of a previous relationship that is certainly getting the way of her relationship with you. Worse, worse.

The only way to end a romantic/sexual relationship is with a clean break. You can still be friends but the regular contact, both in person and telephonic, is what is being the problem. The two of you need to establish the limits of "friendship" and it would be worth your while to have a professional referee that discussion.