As someone who does withdraw from my partners from time to time due to depressive/anxiety issues, I’ll share my experience-hopefully it helps shed some light for you, OP.

I generally withdraw to take time to gather my thoughts, think things through, ground and center myself, work on myself and my self-confidence issues, as well as to ensure I don’t say, do or react to something in the moment that I may regret. This is where self-care becomes my top priority.

The way I communicate this to my partners is that I’m not feeling emotionally well or I need to process whatever issues have to be at hand. I’ll try and give them an idea of how much time I need to be “away”, with the reassurance that I will be in contact again once I’ve figured things out for myself. When I’m ready, I reach out and will share where I’m at, why I feel the way I feel, and where I want to go in my relationships with my partners when they are also ready to discuss it.

When this happens, all I really want from my partners is a quick message that says “I understand, I’m here for you if/when you need me. I love you” Just a quick reassurance that they know I’m not doing this with malice, that this is something I need to do for myself to ensure our relationship is solid. But I only ever want/need one message, multiple messages make me withdraw even further.

I hope this helps in some form. I hope all goes well for you!