Hello - welcome to the club: membership is not optional.
It is truly the most awful of experiences because you will be a) blaming yourself; b) wondering, and therefore, worrying about her mental health; c) panicking about how the hell you are going to survive; d) devastated that what you believed you had, you hadn't. That is the most bewildering part of the process.
There a no quick fixes - although I found some solace in reading a few self-help books. I could recommend some if you find it helpful.
You say you are not married, and you're renting so you've got a clean break now. I'm afraid the legal remedies for co-habiting couples do not exist. However, do you work? How did the two of you manage financially? What about the tenancy is it in your name, shared names. You may wish to visit the CAB to discuss the practical arrangements of adjusting your life so that you don't cause yourself further trouble (e.g. council tax, paying debts etc). Whatever happens, do not allow your distress to overlook safeguading yourself from debt/CCJs/paying bills etc. This often happens in the first months when you are floored.
On an emotional level - I will tell you something that you won't believe:
It does get better. You will heal. You will find happiness again.
It is just not a switch that you flick to make that happen.
The first few months you'll find yourself crying randomly, lurging from hurting to hating, to confusion to paralysis. This is all a normal way of processing the most devastating of news. It does not remain the every five minutes of fresh hell that it feels like now.
The best advice I can give you is to talk, talk and talk with friends and family. Admit what's happened as soon as you can. You'll be amazed at how supportive friends and family will be, go out as much as you can, even if you don't feel like it.
I didn't find counselling helpful at all but others do and therefore, especially if you are reluctant to talk to family/friends, find it helpful to talk with a counsellor.
I hope this is of some practical benefit to you. I'm very sorry that you are going through this, it is truly an awful thing to experience. Best wishes.
And if nothing else: here is the script: the maddening process of being dumped, which you may find helpful in predicting what is going to come next...
www.mumsnet.com/Talk/relationships/a1527705-Midlife-crisis-this-is-the-script