LIFE SUCKS

I have no future in sight...

Hello I'm 20 years old and struggling, it's taking me quite a bit to ask for help but by this point I'm rather worried. Basically, my girlfriend of three years split up with me after I found out she had been cheating on me for the past two weeks. For this I don't blame her as she wasn't feeling the same for me and felt a little trapped and didn't want me to do anything stupid, so naturally her feelings wandered. She isn't seeing him anymore now out of respect for me. This being the main problem certainly isn't the only one, the second being my mother. My girlfriend and I split just under two weeks ago and my Mum told me she didn't care and then I quote; "I don't have to be nice to you when your dad isn't around." This is something she said to me. I can't tell my Dad because it'll tear apart the family and my younger sister of 15 isn't the most stable minded individual as it is. I almost took my life a few days back, in the garage with an old tie as a noose around my neck. I stopped as I suddenly thought, "How can I do this to her..." Her being my ex-partner.
I still see her as often as I can as I feel better when I'm around her, but at some point she will move on and find another man... To which I don't think I can cope. We went out for a meager three months 4-5 years ago and the whole time before going back out(3 years back) I still had very strong feelings for her.
I know myself, despite what people will say that I will always have strong feelings for her. She simply is the reason I am still here today to write this.
I just can't take it all, I'm dwarfed by all these painful thoughts and have sat in my room in tears for almost 2 weeks now. I don't expect to get better overnight, but I'm blocking myself by saying that I don't want to be happy without her...
I don't even know why I'm writing this, I know that all the advice in the world won't help my stubborness towards the situations.
I have no job and can't find one to save myself, yet I need to get out of this house. I had been planning on moving in with my partner at the time, but I highly doubt that card is still on the table.
My life is just a mess and I can't see a light at the end of the tunnel. Ever since we went out the first time 5 years ago, I kept comparing other girls to what it was like with her and so, didn't get anywhere with anyone else. I know it will be the same thing this time around.
I don't know if I'll ever check back to see if there's any replies, but if I do I'll make sure and read them.
Note that I don't really have anyone to call a friend, only her. She is my best friend and I can't bare the thought of a life without her.
I obviously don't expect anyone to understand as nobody has lived my life or knows how I tick, but everyday I think about killing myself, as stated before, the only reason I haven't and probably won't is because I can't do it to her.