How to Handle Mental Health Affecting Relationships?

What do you do when your depression, anxiety, PTSD, or any mental condition affects your relationship in a negative way? I've been with my partner for over 7 years, and my depression has increased this year more than ever and it's really affecting him and makes him super stressed out and worried to go to me when he's struggling because of how much I'm struggling. He never really sees me happy and that's not his fault by any means, but I hate that he has to see me like this. I tell him I'll get better and never improve, I tell him I'm fine so that he won't have to worry. He is my safe place, but I don't like worrying him so I kind of have to act normal around him since all he sees is me stressed or depressed and he doesn't deserve to see me that way. Any advice or suggestions or stories related to this would truly be appreciated! 💕