My depressed partner drains me

tl;dr: My partner has been depressed and not knowing what to do with his life for a long time. I am the only person he relys on for support and I can't bear it any longer. It starts to severely affect my own life quality and happiness.

I (30/f) met my partner (32/m) at university eight years ago. He was a very fun, open and active guy with a huge social group. After two years of being friends we started dating. It was around that time that he was done with all his courses and papers and the only thing left for him to finish uni was to write his bachelor's thesis. That didn't happen for another four years.
Within that time he basically didn't do anything. Didn't write his thesis, didn't get a job. He told me, that he had no clue, what he wants to do with his life and I tried to encourage him to just do some internships to figure that out, but he never did. He is fortunate enough that his parents pay for his expenses (always did and still do), so money wouldn't be the problem. He never did any internship.

Fast forward six years and the situation is still the same. He did eventually finish his bachelor's and started a master's degree but realized that studying just isn't for him. However he still isn't properly searching for jobs or internships or general input that would help him figure out, what he wants to do or be. The thing is, that his self esteem is lower than the mariana trench. He feels like he doens't know anything and is underqualified for basically every job. He's not. He's incredibly smart, attentive and detail orientated and has a great passion for social justice but he keeps telling himself that he isn't enough for any job and he doens't dare to apply. I don't know how to help him. All my affirmations seem to not penetrate his mindfog. However, the problem is that I'm the only one he's talking to. Because he realized that all his peers moved on he stopped having contact with them because he was embarassed.

So here is the thing. I know he's depressed and I know that he is busy with surviving day to day. But I'm pissed. I sometimes get so angry and frustrated with him. He doesn't go to therapy and I don't know, if he really tried to get a therapist but the waiting lists are too long or if he didn't try hard enough. He won't tell me. Same thing with his job situation. I don't know, if he is searching and for what. Everytime I ask him, what he wants to be or do he tells me, he doesn't know. And I started asking him really deconstructed questions like "what kind of activities (writing texts/organizing events/making statistic sheets/etc) do you like?" "do you want to work alone or in a team?" "what goals (helping people and what kind of people/income/etc) do you want to be met?" and so on. It's always "I don't know."

I am getting really impatient. It's been six years and he has so much potential that he doesn't see or use. Everytime I suggest something, he doesn't use that info, but feels stupid, becaus he didn't have the idea himself. Doesn't matter that I keep reassuring him that it is okay, to need help or not know everything on the spot. He feels stupid and blocks any further conversation and than i find myself trying to calm him down and in the end he promises me to change things, but never does. Probably because he really doesn't have the energy, I get that on an intellectual level. I understand it. I still feel extremely frustrated.

This whole situation keeps our life on hold. It didn't matter to me for a long time. I always told myself, that he will find his way and that he will figure everything out, but now we are in our thirties and I really want to start a family. I want to get married and have children and start the next chapter. I can't do that with a man who barely survives. And it starts to severely affect me. I get so impatient with him and sometimes I find myself blaming him and I know, that is a terrible thing to do to a depressed person and that i should be patient and understanding. But I'm carrying this alone, because he doesn't talk to anyone else about his struggles.

The worst part is, that he has been away for two weeks to look after his parents' house while they were on vacation and I have felt so good! So so good! So free. I started singing again while doing chores and had a dance party with myself and there were a lot of those little signs of being happy again. He's back home now and I feel like I'm suffocating. I didn't realize it at first, because we're always together. But I feel like I can't be happy, because he isn't. I feel like I can't rejoice over my little victories because he has none. I want to talk about my masters and my ideas for work and all the new input I'm getting (I am studying for a master's degree btw), but I feel guilty, because he isn't passionate about anything. I feel like i can't live my life because I know, that everything I do reminds him of all the things, he doesn't (earning money, socialize, building a future, personal growth).

I really do love him and I don't want to break up or anything. But I also don't know, how I should move on and how we can survive as a couple any longer. I need to breathe but I can't.