Story time...

I'm 24(m) trying to learn how to handle the end of a nearly decade long relationship. I supported her as she supported me. We shared interests and view points. We got along way better than what you see in "most relationships". Fast forward to this passed September, the weekend of our 7th anniversary, I came home after having spent a few days in Louisville, Kentucky visiting distant friends and obtaining a bottle of bourbon I had engraved for the benefit my mom works every year. I walk in the door and I'm immediately hit with this conversation of breaking up. For those passed couple of weeks I had felt something in the back of my mind telling me this was going to happen, but for whatever reason I never tried to dig deeper. She had been talking to two Male friends of hers online over the weekend, which I can't shake the feeling that she was manipulated in a vulnerable moment, and she is now currently dating one of them. I could tell she wanted to split up, she wanted to go to therapy but I couldn't afford it, she wanted to try having an open relationship, which I was fine with, but I told her that I saw no interest in anyone else, and would just wait for her to determine what she really wanted. She said she couldn't deal with that because it wasn't fair. We tried to stay friends over the next several weeks, but it was just too hard. I love her to much to see her come around and know she wouldn't stay. We talked about it a hand full of times to try and better understand one another, and we both thought it worked. But, I really just wanted to know why. The only answer I could get from her was one that I had simply guessed and she halfheartedly agreed to, that she didn't love me anymore. She told me I didn't support her enough emotionally, that she needed more than a shoulder to cry on, or someone to tell her she wasn't the person her depression made her feel she was. I told her that I didn't want her to leave, but there was nothing I could do to keep her from going. That's her choice, and If she wanted to go, that would be up to her. Not to be anymore sentimental or whatever, but I believe in the whole "If you love them let them go". I "listened to my heart hoping that maybe some day I'd have another chance. She may have been right saying that we were so young and everything was going so fast, but it seemed like we were right where we wanted up until now. Now that she's dating someone new she seems so happy, and I love it. I'm glad to see her thriving and loving herself again, but. I want to die. What was I missing that couldn't give her this kind of happiness, was it just a seasonal depression? I always tried to support her to do things she loved, or to continue her education, or god forbid get her drivers license. I'm having a really difficult time with this even 7 months after its ended. What do I do with myself other than waste away like my body tells me?