Hey man just wanted to offer some words of advice as I went through the same thing. Dated five years, engaged 1.5 and she got cold feet 1.5 months before the wedding and ran. I know you think it's bad you had moved in together but we had bought a house (thank god I was alone on title).
Couple of things, you're going to be asking a lot of questions of yourself the next few weeks. What if's, why'd she do it, what if I had done this or said that ,was she ever really happy, etc. You'll entertain lots of fantasies about how she will realize her mistake and the magical reunion will take place. Most important thing here is let yourself feel. If you're sad, feel sad, cry if you have to, if you're angry be angry, get pissed scream, if you're nostalgic reminisce about a chapter of your life that's now over. Dont try and bury or hide things from yourself, it's ok to not want to be that way around others but you've got to be honest with you.
Two, stay busy. First things first is living situation. Stay active, at work try and focus on work. Keep yourself occupied. Get that new place, plan appliances, you don't need that kitchen stuff immediately but plan it out. Get ideas of what you need to do and make lists. Check things off list. Lists are great because they're concrete evidence that your life is moving on. That you're still moving forward and doing. Gym is also part of this. Exercise for the endorphin benefits alone is key here. Even if you don't feel like it fake it. I can't tell you the number of times I felt better after the gym when I had to drag myself to it. If i I didn't want to go I said i would get there and change and do one lift then leave. Turns out once I was actually there I didn't want to leave. The benefits help your body and mind.
Three, Friends and family. Spend lots and lots of time with friends. If you'd normally watch a game alone watch it with a friend or group. Go out a lot. I can't tell you one of the best things about my broken engagements was how it rekindled friendships. When you're a serious couple you don't devote as much time to friends, especially single guy friends as you should. even if you haven't been active with them in the past as you'd like, they want to be there for you now. that's the amazing thing about guys man, we can resume a friendship in an instant. Do it.
Four, Go on dates. This isn't immediate and depends on what you want and feel you’re ready. For me this was about 3 weeks after the broken engagement. Don't date seriously. You're not going to be in a serious relationship a month after your break up. You have to be learn to be single again. Don’t run to the comfort of the first relationship that comes along just because you feel safer in a couple. Lots of people do this because they don't know how to be single again after so long to stand on their own. That type of thing always backfires. These months are about finding out who you are post breakup and who you want to be. Try and have fun. You won’t. But fake it. Try and sell yourself as the fun person who is curious about life again. Sleep with girls. Have fun. Don’t take out broken engagement issues on them and don’t make them your therapist. (side note if you want see a therapist, its great to have an impartial person to talk about where you want to go and organize your thoughts). After being with my fiancée for 5 years it was refreshing to see other people again for one simple reason. This will start to remind you of all the possibilities ahead of you again. Some girls will rock you in bed in ways that surprise you because you’re used to only one person. Some will have fascinating hobbies you get into, some will be terrible terrible dates that turn into a funny story. Don’t run away with future marriage fantasies in your head, they will happen but recognize what it is and be focused on the now.
It’s hard but you’re eventually going to see this for the chance that it is. You now get to choose a future version of yourself that is completely different than what you’ve thought for years. That can be a good or bad thing depending on what you do. Figure out who and what you want to be moving towards independent of anyone else.
One big key moment for me was after a conversation with my Dad. I knew he had been engaged before he met my mom and got broken up with by his fiancée also. He said it’s tough, I’ve been there but life will get on and you’ll be ok. After this conversation I realized something important. My entire existence was predicated on a broken engagement. It was a good thing that that bad relationship ended for my Dad.
There’s a happy ending out there for you. This happened to me about 5 years ago. It was my college gf, turned fiancée. I swore she was the one. Thought the relationship was great. I met my wife about 5 months after my engagement ended. I couldn’t possibly be happier now. The further away from the old relationship I got, the more I could about how unhealthy it was in many aspects and how it just wasn’t right. I wasn’t wrong for trying to make it work but it wasn’t the right relationship for me. Knowing what I know now I would be the happiest man alive at the point you are now at. You probably will be someday too. This is the event that is going to make your future happiness possible. You can’t see it yet. I’m further along in the book than you but it’s there man. People want to help.
Take care brother. You’re gonna be alright