How can I prevent our problems from coming out again?

me and my g/f have been together for 2 years on and off. I cheated on her twice over a year ago and I've dumped her 3 times. this is the longest weve been steady now(5 months). she told me when we got back together this most recent time that this is my last chance.
I kinda provoked a fight this morning over her not providing me enough attention because I feel that she always has time for other people but not me. maybe I just feel that way outta fear but she said we should take a break, than she said we should break up! we decided to drop it after a few minutes of subbornness and crying on both our parts and sorted things out later. we talked for a few minutes about our fears over each other before she went to sleep just now.
we both keep having dreams of break-ups, her ignoring me and her cheating on me. we both have emotional problems so we tend to clash when things go south for just a few minutes. im still upset about this morning, even though we smoothed things over. we know we love each other but it was the first time she threatened to break up.
I guess what im trying to ask is, how could we prevent this from coming about again? weve had problems expressing feelings to each other before. shes afraid of having a breakdown and im afraid of doing something rash(going back to drugs). im also afraid of what she would do afterwards because she tends to get wasted after a break-up and go on the rebound. any suggestions??? (sorry, long story)

OK, well you have obviously already made the decision to get your life together and make your relationships work.
So why is it that you are even thinking of going back to drugs?
There is always a better way- and this is it, yours for the asking.
Anyway- I know about this kind of relationship stuff with 2 disfunctional people- and there is a book which TRANSFORMED my ability to have GREAT relationships.
It may suprise you, but this information is what you need, the subject material covers a lot more than you might be thinking it does. And its all really simple and fundemental stuff. You will enjoy learning about this stuff and seeing instant changes in your life which will give you so much confidence about your ability to make any changes to your life that you need in order to have a better life- easily.
The book was on loan and I no longer have it, I dont remember who wrote it either.
I have done a little online search for this book and have not found it yet- ! will let you know if I find it.
Its called Boundaries, but so far I have only found a book of the same topic and same name by a guy called Dr Henry Cloud - this is not the one that I read, but it might be good for you to get in Lieu of... If you can handle the Christian overtone.
Ps I had a very bad upbringing - the worst kind. My longest relationship prior to this book was 1year. All of those relationships were traumatic most of the time.
I met my current B/F a few months after reading this book, we have been together 11 years. We experience a lot of love, fun and enjoyment of each other, we express appreciation and gratitude towards each other daily, in a natural and uncontrived way. We feel safe. calm and loved. We talk easily about any 'problems' and it feels good to talk. We never fight or hurt each other and we don't do much withdrawing from each other - only for a short time, if we need to sort out something inside ourself.

ok- I found it ! :-)))
http://www.amazon.co.uk/Boundaries-Relationships-Knowing-Protecting-Enjoying/dp/155874259X/ref=sr_1_6/202-8771976-2746265?ie=UTF8&s=books&qid=1191494857&sr=1-6
And here is a review that I particulary agree with;
This to me is one of the best books ever written on boundaries and relationships. Talks of the structure of a person's boundaries, ways to know where your boundaries are, the necessity of having boundaries within your relationships. Written with sensitivity and love. Anything further that I could say about this book would fall short of its quality. I consider this a must read for anyone from any kind of dysfunctional background, especially those struggling with boundary issues.
---
Here is also another book by the same author which will be of interest;
http://www.amazon.co.uk/Healing-Child-Within-Discovery-Dysfunctional/dp/0932194400/ref=pd_bxgy_b_text_b/202-8771976-2746265?ie=UTF8&qid=1191494857&sr=1-6

I am not sure those links to amazon posted correctly, so you may neeb to search for these titles yourself.
Boundaries and Relationships: Knowing, Protecting and Enjoying the Self (Paperback)
by Charles L. Whitfield (Author)

and
Healing the Child Within: Discovery and Recovery for Adult Children of Dysfunctional Families (Paperback)

relation ships can be hard you just av to work at them. its best just bein honest about your feelings with her what av you got to loose. if you dont tell each other how you feel its not going to work. an you cheatin on her wouldent of helped she mght not trust you deep down inside. you have both just got 2 av a long talk about the things you are both worryied about an sort them out. no point of tellin us on here you need 2 b tellin her.

...well I dated this guy last year for like 10 months...everything was perfect...and then it started being all rocky...I dont think I was ready for that serious of a relationship..still I loved him so much it didnt matter...
so you have to be prepared to work at it...dont hurt her...girls have complex emotions

yea, girls are complex. we talked about all this. shes over me cheating on her and has been for a while. we are prepared to work at it, this was just a bomb waiting to go off. we had kind of a power struggle for about a month. we talk all the time, but sometimes we drift off. we agreed to have a looong talk tomorrow anyway. we just need to express ourselves without being so negative or hurtful. we love each other a whole lot so well probably stay together. we werent really thinking rationally at the time of the fight, we both had bottled up feelings. we were both thinking of break up for a while we just never mentioned it. we both kinda switched roles in the sense that shed always have to call a lot and I wouldnt pay attention but now im the one calling and shes just too tired to pay attention. its really just a matter of adjustment its her first month in college after all so things are tough on her. I guess im kind of overwhelmed because shes going to school and workin and I just work.