My ex-gf is contacting me via text; is she interested?

First I would like to apologize if this is in the wrong section. I'm looking for female advice, so I thought this would be the best place.

Twice in one month she has contacted me. Once asking if I was back in town (I left for 2 years), another was a mass text to all of her phone contacts to go out, but turned into a seemingly innocent personal invite after I replied. I wasn't able to go, but I'm wondering if she's interested again. It would help if another female could weigh in on the subject.

A little back story might help, so I'll give you the short version and hope for the best.

We were together for roughly 4 years, a breakup and makeup in there somewhere, but ultimately deeply, madly in love (or at least I was with her). Long story short, I had some problems coping with life, nothing suicidal or weird, I just became withdrawn, stopped going out with friends, was angry often, never raised a hand to her, but I just wasn't myself. I had a very hard time with this for 2 of our 4 years together, different medications, a surgery and some self-help did not work, eventually she had enough. She broke up with me in 2008. She was the strong one, didn't cry, told me that it was over and watched as I cried like a baby. Pretty cold stuff.

*Edit: She stuck with me through the worst of times, but eventually she couldn't take it anymore.

After a few months I moved on, found a new girlfriend, got over the coping issues and got my life back on track. I fell in love and things were going fine... with one exception. I've never stopped thinking about her. It's been a little over 3 years and she's never left my thoughts. Not one day goes by without me thinking of her or dreaming about her. I don't know if the feeling is mutual, I can only hope, but this was my best friend. My soul mate, the woman I would live or die for, and who I truly believe I belong with. I don't think that I could ever love someone as deeply as I did her. As if my deepest emotions were spent and left with her.

*Edit: The "deeply in love soul mate" feeling was mutual for most of the relationship. I think my problems took away from those feelings on her end.

I'm not the crazy "if I can't have you, no one will!" type, if she is happy without me, good. But if there is a chance... I just don't want to blow it.


Even shorter version:

It's been 3 years, she's never ever tried to contact me in a friendly way, recently she has twice. Is it possible that she may still have feelings for me, or is she just being friendly? Keep in mind she was cold during and after the breakup, then simply silent for years.