I have never left a relationship because I thought it might improve depression, but I have experience of depression. I saw that you’ve had no replies and didn’t want you to feel like nobody is listening.
It’s an extremely complicated condition and often very hard to pin down causes and reasons. It’s also a truly awful condition which sufferers just want to come to an end, so it’s very understandable and common when suffering, to start to question every aspect of your life and start thinking “Maybe if I changed my job/ partner/ home town/ house/ got away from my family etc etc it would lift.”
Also, don’t forget that at present, your life is being viewed through the filter of depression, which gives you a limited or negative emotional response to things and people which used to bring you joy. Those things and people are still there and when you are well again will probably make you feel exactly as they did before. It’s really hard and very confusing to know what you actually feel or think about anything. Bloody awful condition, not ever to be underestimated, so don’t be hard on yourself.
Was the onset a recent one-off, or have you suffered from it on and off throughout/ before your relationship? Can you pin it down as reactive depression to a specific event? Did it develop as a response to something your partner did/ is doing that you haven’t tackled and have stuffed down and put up with? Depression can be due to losses of actual things (a job, marriage etc) or a loss of a belief or idea about yourself or others : “I thought he would never cheat on me/ be so distant etc” or “ I thought I was a clever person but I can’t be because I didn’t get that qualification/ job offer” etc. It can also be because if unexpressed anger or ongoing resentment that you have constantly denied or stuffed away for the sake of a quiet life. Good counselling can unpick all this confusion and I wouldn’t make drastic decisions about any aspect of your life until you have talked your feelings through with a professional.
Have you suffered from hormonal problems before depression took hold, such as PMT, or if you have children, did you get PND? Sometimes it’s a medical problem which can be solved that way.
Sorry not to be much relationship help, but all I will say is that those closest to you can sometimes seem irritating or hopeless when you suffer from depression, or show a lack of patience or compassion sometimes (it’s hard to live with a depressed person and even someone who lives and cares for you very much might be a bit snappy sometimes, it’s usually frustration at wanting you back to how you were and wanting to help you but not knowing how) when you need support.
It doesn’t mean it isn’t your relationship making you depressed, but it might not be, and you need proper professional help to sort it out and help you find out what you really feel. Randoms here won’t be able to help you know that, if it was that obvious you would already know. Leaving might make you feel better, or when you recover and feel ok, you might have made a decision you regret. Find a counsellor and look into the causes of depression to see what resonates best with you, before you do anything drastic. Take care OP and you can message me if you want to, I understand depression. It can make you feel alone even if you have loads of people around you. X