Recent Breakup

I just got out of the best relationship i've ever had. He treated me so well and helped me heal from everyone who's hurt me in the past. He taught me how to let go of the past hurt i've bad and think about how bright our future will be together. But now it ended. All because my anxiety and depression got the best of me, and I didn't get help soon enough, and because of that, it was to much stress on our relationship. I understand why he left, but it still hurts. I just don't know how to heal from this when he was my biggest supporter. Not only do I have to learn to cope with my mental heath, I now have to cope with losing someone I thought i was going to marry. It's so hard to understand how things are going to get better. All i want is to be able to talk to him, but he needs his space. I respect that, but it's just very hard.