I've tried both. I have a chronic health condition and social anxiety, so a lot to carry around. I was in a 14-year relationship with a guy who couldn't deal with it. He didn't know how to handle the health thing, and he didn't really believe in social anxiety. My health condition didn't manifest itself until we were together, so it was a surprise for both of us and it didn't jive with his expectations for our life. Being in that relationship was really bad for me. I tried to live as if I didn't have physical and mental health problems. I felt so alone and broken. It led to depression and in the end, I left him.
After that, I feared I was doomed to be alone. But I was lucky enough to find a person who's super supportive and I'm now blessed with a healthy relationship. The difference between these two relationships is like night and day. One tore me down and the other build me up. So in my experience, the bad partner can make it a lot worse while a good partner can make it all a lot better.