I have an ex girlfriend that I dated for 4 months and we've been knowing each other since November 2006.Everything was going pretty smooth at the time and we love spending every moment with each other.Then the relationship started going down hill.I used to go through her phone and listening to her conversations to see if she was cheating on me.I used to follow her to see if she was lying about where she was going to see if she was going to see another man.I felt very insecure to what she might have been doing.I messed around with other females and I know that I shouldn't have done it.I don't know if she was cheating or not.We had an altercation and she ask me have I been following her around and I said no,and she asked me again and I finally told her the truth to what I was doing.She kicked me out the apartment when I used to stay with her.I accidentally hit her and she put me in jail or should I say a holding cell.After that moment,we finally started talking again and messing around with each other,because I still cared about her no matter what.We talk off and on but we are not together anymore.We are just friends but I still care about her and want to be with her.She has a new friend that she often talks to.I don't know if she cares about him or want to be with him or not.She says that I don't help her out and we argue all the time about nonsense because she ask me to do simple stuff and I get pissed off.I think she still cares about me but the feeling about me I don't know what to say about that.I watch her son sometimes while she goes to work.She ask me the other night if I wanted her to stop talking to other guys then I should change.Is she trying to use me or is she trying to see if our relationship will grow back again.Can you please help me with this situation?

Wow that is one messed up situation!
First of all, why didn't you trust her? Was it because of her behaviour or your own insecurities? Since you gave no examples of finding her cheating or lying I am guessing it is the latter but either way it is not OK to 'stalk' your girlfriend. Whatever these issues you have are I think maybe you need to seek help about them.
Second, you cheated on this girl. Can you imagine how that must have made her feel? If just thinking she was cheating on you drove you mad, think how she must have felt. Again, I think you need to seek help on this because if you still feel the need to cheat when you are in a loving relationship and none of the other girls meant something to you then I think you have some issues there.
Thirdly, and this is the big one here for me, you 'accidently hit her'. Its very hard to accidentally hit a woman if you are not raising your hands in the first place! But even as an accident, you didn't meantion being sorry for that which worries me a lot.
When you look at it this way, can you see why this woman would want to get back with you? Obviously she must really care about you to even consider it but she is a woman and a mother, she knows this is not a safe or healthy way to have a relationship. She is asking you to change because clearly she sees another side to you. The question you need to ask yourself is, 'do you want to change?'. Not for her but for you. If the answer is yes then seek help and councilling.
Good luck

You need to leave her alone and seek counseling fast.

In this situation, she could be using u since she can't think of a future with a guy who is soooooooo insecure.

Do u expect her to forget about the things u did in the past and welcome u again with open arms? She is merely asking for help with babysitting her son and perhaps looking for companion when she is lonely. U sound more like a "friend for convenience" to me.

Besides, the main question u should ask is not whether the relationship will grow back; but whether u are fit for a relationship or not. Being such an insecure man will ruin most of your relationships. Do consider counselling, like what Talaniman suggested above.

"She ask me the other night if i wanted her to stop talking to other guys then i should change.Is she trying to use me or is she trying to see if our relationship will grow back again.Can you please help me with this situation?"

Good childcare is difficult to find and expensive. Is she paying you fairly? My guess is the romance is over with, so keep dating other girls and improving your relationship skills.