how to help (trigger warning)

I want to know how to help the guy i've been seeing (30 m and 30 fm) on and off for 5 years, he has major depression and recently tried to take his life in early april. he's suffering majorly right now and uses most of his energy to just get thorugh the day. Idk how to help or what to say to show him that he is not a burden on me like he thinks he is and that I do love him (we've only ever said it a few times but thats another issue). he has hardly even talked to me this weekend and I know its because he's tired in every way possible but I feel insecure because the reason we are on and off and not even offcial is because he dumps me when he has a major depressive episode. he actually tried to end things the morning he made the attempt and then later on my birthday because he says he's just going to hurt me and I don't deserve that. this is getting really hard because when he does feel better and does stuff like go to a party or hiking i'm not invited, so i don't feel important to him or like I'm part of his life. Idk, its stupid to worry about if he cares about me when he's so depressed but I just want to know if anyone can give me advice on what to tell him or say to encourage him.

Basically, when you're at your worst and darkest, what is it that you wish you could say you want from them or wish they would say or do for you.

Any insight is greatly appreciated. thank you