My relationship has fallen apart, and it's no one's fault.

This is extremely complicated and difficult to explain. Me and my boyfriend were friends for 5 years (best friends) and we started a relationship a year ago. I truly believe that this man is my soulmate, the connection we have goes beyond love, he is like my other half. In recent months both of our mental health began to deteriorate. I started really trying to focus on my health and get myself back into a good place, he began to always worry about me and put me before himself, even when I'd tell him that he should worry about himself. He started stonewalling as he became more depressed and as my health got better I thought maybe I should put myself out more and show him that my support is always there. It was a lot of back and fourth, last month we almost broke up because he said that he couldn't cope and that he just wanted to shut himself away, but he then changed his mind. We got him to a doctor and he's awaiting further support so that's amazing. Last week though, out of nowhere he told me again that he cannot hold up his end of the relationship, I've been telling him he doesn't have to do anything but focus on him and I'll be here, he told me how much he loves me and how unfair it is for me to be left hanging, but again I told him that I'll stand by him with everything, nothing matters to me except him getting the help he needs and not having the pressure to be a boyfriend to me. I don't know if we are together or not, we haven't had any contact with eachother for over a week. It's difficult for me because I don't really have friends or anything, I took a big leap of faith getting romantically involved with my best friend, but I've had the best year of my life. We've never fought, we have disagreed and discussed things but we've never been mean to eachother or anything like that, we still love and respect eachother. I know we both want things to work but he needs to step away from me so that he can stop worrying about me constantly and really focus on himself. I know this is what's best for him but it doesn't make it any less painful for me. I'm a very anxious person so it's hard to reassure myself. I know deep down that because we have such a strong connection and love for one another that we will be okay and I'm sure that when things stabilise we will talk and figure it all out, but my anxiety doesn't speak so kindly, my anxious brain tells me that he won't ever return and that he's sick of me. It's hard not being able to know if he is doing okay, knowing how low he's been it's scary stuff, even through the ugliness of depression this man is still so beautiful, he's the love of my life, and I've temporarily lost a part of myself, I'm just trying to navigate this time. My relatives aren't exactly supportive, they see his depression and need for his own space to heal as selfishness and say it shows he doesn't love me. Those words from them definitely add to my anxiety, if I could ask for anything it would be reassurance, I know he loves me, more than anything. Also, when we reunite, how can we navigate his problem with putting me before him, as long as he does this he will fall back into this cycle, maybe it'll be significantly easier once he's able to manage his depression, has anyone here ever been through this? Or knows how to deal with this? It's so complicated because of mental health that I simply do not know what to do. I'm sorry for the lengthy post, I just love this man so much and we are great together, the rapid deterioration of our mental health left it impossible to work through it all for the time being.