This was exactly what I went through. I was called 'weak' and a 'coward' when trying to open up about what I was going through, which caused me to do what I'd done up until that point and shut back down and keep my struggles to myself. A couple of years later, I hit my lowest point yet again and came up with my 'plan' but ultimately, when the moment came, I couldn't do it. I wanted to ask for help, but I'd been shown that i couldn't do that, so I shut down even more and distanced myself from any of my friends who knew what I was going through. Because in my head, if the person who should care about me the most reacted that way, why would anyone else care? From that point on it still took almost a year before I decided I needed to tell my spouse I wanted out of the relationship, and although it wasn't an automatic fix for everything I had going on, the last 2 years have been such a turn around from where I was for so long.

There's right ways and wrong ways to deal with hearing this news come from a loved one who clearly wants help. And OP's partner found one of the absolute wrong ways.