My [24F] fiancé [25M] of 7 years left me for another woman [28F]. I don't know how to cope.

I'm devastated, to say the least.
We have been in a relationship for 7 years, engaged for 2. I've battled depression for years and just recently have been getting real help for it which I believe has impacted our relationship. I was getting better until this all happened. We agree on all major things like money and kids, we can talk through arguments, and we support each other. I'd say in the last year the spark has faded, but I've been working on my depression as I believe it's a factor. I love his parents, they love me.
In the past couple of days, I noticed him acting very strangely. Saying how he's reevaluating his life, how he knows I will have a bright future (not we). I asked what was wrong and he confided that he has a crush on a coworker.
Him and this coworker have been friends for a few years through work. Nothing suspicious ever popped up. They play sports every so often and now share the same career path. Now lately in the past month, he's been obsessively studying her native language, looking at her social media, and texting her. Seemed like every 5 minutes her name is on his Message screen.
Now, this has happened before. It was sudden, out of the blue, and was a red flag for depression because of this. I told him such and all was well and we were stronger than ever, mostly because he said he felt he could trust me with anything and rely on my support for anything, no matter hpw difficult.
So this time around, I said the same thing. I asked if anything was wrong with us and maybe he's projecting things missing from our relationship on her. He said absolutely, all seemed well again. He said he's taken a strong interest in her cultural background. I figured okay, let's work on it and give it some time.
The very next day, he posts a picture of her on social media. I said that it was very disrespectful given what was said the previous day. He doesn't take it down, the texts continue.
The day after that, yesterday, I had a terrible time at work. All I could think about was what they were texting about. I come home and he's texting her. Tears ensue. He says he doesn't feel happy in our relationship and wants to be with her. I found his post on this Forum Section explaining that he's professed his love for her already and wants to move to NZ with her. His search history has things like "how to date a (her nationality) woman", "how to date an older woman", "how to leave a fiance", and "how to break a mortgage". Also tons of porn of her nationality. I have stuffed a trash bag of clothes for him to go to his parents for a while, maybe permanently.
I am so heartbroken and don't know how to cope. The biggest part of my life and my biggest support system just evaporated in an instant. He's been in an emotional affair with her for a month so has a great support system through her. I don't know how I'm going to be able to work on Monday. I need to finish a class to go study abroad in September but I can't even fathom how I can do it. This seemingly came out of nowhere. I don't know how I can ever trust a man again or even find someone with the same priorities as me. I'm so lost.
Tl;dr: My fiance is leaving me for another woman whom he has had an emotional affair with for a month. I am so devastated and don't know what to do with myself.


Source.