7 year relationship blindsided because she caught feelings for someone else

She had been sitting on the idea for some time, now I know. She's a wonderful person and when she started asking me when we were going to marry, plans for the future, etc. I commited and asked her to marry me in our dream trip.

One month before BU she told me I was in a negative and disillusioned spiral and was hurting the relationship, and asked me to work with a therapist. I hadn't realized this before, so I immediately went and fixed my attitude. I wanted to bring good energy to the household.

One week before BU she asked me to look into a shared bank account, we planned a summer trip, been looking at a new tent to camp, and some properties and land to purchase in a future. We were planning our wedding together, she kept telling me I was her type, how I was turning into a handsome man, big hugs and watching movies together. I kept telling as always how beautiful she was, she was getting into shape, I kept comforting and taking care of her as always.

Come monday, she tells me "she has lost feelings" and that "she has to leave because of an instinct" because she feels we're more "roomates than a couple". She was very sweet the last moments, hugging, kissing me, thanking me for the happy years together. Gone in less than an hour, like that. She emptied our flat of her things, it's an empty husk now.

I've been devastated, trying to search what I did wrong, going to therapy for a month. Reached out to tell her I was in the process of recovering, got an apology for it all, and I asked for some more time before we could talk.

Now I asked a mutual friend, who was reticent of telling me to not hurt me further. I told him I deserve to know at least the truth. She had been falling for someone else for the past year but had doubts and didn't want to ruin our healthy relationship. She finally caved in and left.

Right now I'm in ruins, I genuinely couldn't have imagined her doing this to me, after all the years, sacrifices, patience the relationship took. At least I have the comfort of knowing I did my best and did nothing wrong, but I'm conflicted about contacting her one last time and confronting her for my own closure. The doubts of a crush shouldn't be enough to ruin our life together. I'm afraid she has already closed this chapter in less than two months and moved on with her life. I don't deserve this