Symmetrical I know how hurt you must be but this situation WILL make you stronger than you can ever imagine and you have to believe me on that.
It can take a bit of time, sometimes longer, but once you get over this you will enter future relationships with a much more reasonable mindset. Its just bad to have expectations in general like marraige, or that any situation in life will last forever.
I've been in really low spots in my life where suicide was on my mind 24/7 and I'm so glad today I never did it. I mean imagine preparing to go to college and you get thrown in prison instead. Then the entire time your in prison people are trying to take advantange of you because you're also getting clean from drugs and very mentally vulnerable. I got the crap beat out of me, thrown in lock up for it, and on the 9th day tried killing myself. I just can't describe the amount of emotional torment I was in at that time of my life.
I honestly think a lot of times people who attempt suicide are not trying to escape life as in living, but the specific life they are living right now. And I also believe thats why so many people don't succeed at suicide, they don't really wanna die, it can actually sometimes serve as a survival mechanism to get you the attention you need.
I remember getting out of prison like "I can't wait to get back to school and find a girl". I was so ready for the "easy life" and of course I got my heart ripped out my first year out. I was ready to go back to drugs, I was ready to throw the towel in once again, but I was fortunate enough to find a person who took great interest in my situation and helped me turn it around for the better. Grad school is stressful I can imagine, and this is the last thing you need before finals. But something I've realize about life which always helps me now, is when seemingly bad things happen in your life, just don't think about them right now. Its always better to think about it a few months down the road with a more objective mindset. I honestly don't trust my own emotions anymore when bad things happen, and I've been able to detach like that just temporarily till the pain passes. It does help me a lot. And once the pain isn't so fresh you really can look back and see the situation for what it was, which was a terrible reason for anyone to wanna take their life.
You need to focus on yourself and your own health. You trusted someone, and had NO WAY of knowing they would do this to you. Any other person could be in your situation and it says nothing about you as a person. These terrible things in life can either break us or make us. Its the simple fact. And if you don't let it break you, at some point its inevitable it will have helped you out in the long run.
I also study relationships for school and was in the seduction community for 4 years of my life. A lot of the men I saw come into the community were recently divorced/broken up and suicidal. And I cant stress how important it is to fight the impulse to isolate. You NEED to talk to people, women, guys, anyone. You need to realize how many people are in this world and that no one single person is worth feeling this much pain over (except family imo). You will find a better girl with higher morals. Just take this time to work on yourself, don't get into those intense moments of thought that lead you to feeling like shit, ALTHOUGH it is very important to still mourn. Its ok to be sad, but it is NOT ok to ever be angry at yourself. Seperate those feelings and I really believe you can get through this trying time of your life.