[Angela]

I think you both would benefit from direct conversation. At this point you're both only speculating about what the other is feeling; why not clean it up? How about something along the lines of:

"Woman, I really enjoy your friendship and would like to continue it. I behaved in a way that did damage, though, and I'm very sorry for that. I felt an imbalance between us -- I think you've felt it, too, right? It has made me uncomfortable, and I reacted by withdrawing completely. I'm sorry, I wish I could have handled my feelings more directly, and I'd like to clean it up with you now, ok?"

Be sure to give her a chance to tell you how she feels.

Let her know that you feel you both need safe, appropriate boundaries, and that you've experienced this from another perspective. (Actually, that's why this is the perfect learning experience for you, Sarah; you're seeing your own issue reflected in another person.) Talk about what you both feel is appropriate -- e.g., 2 or 3 10-minute phone calls a week feels right to you, and that you'd like to let go of the maternal role you've been feeling. Tell her that more than that makes you feel like your boundaries are unsafe. Ask her what she needs in the friendship to feel safe and valued, and be honest about whether or not you can fulfill those needs.

Once you've forged your agreement about boundaries, let her know that you're committed to talking about any breaches or issues the moment they come up. Don't let each other get away with not having integrity. It is not easy, and you'll probably screw up, but remind yourself to be really present in your relationship and to say what's so without clutching it and letting it fester.

Tell her you're grateful for your friendship, because you're both the perfect opportunity for each other to learn something really valuable in your lives.

How does that sound?