Of course it wouldn't be a deal breaker. Everyone has their rough patches, and sometimes coping can be hard. It always starts as a choice, but it might not seem like it and sure doesn't end up that way. So, no, not a deal breaker that a girlfriend once had to re-learn her value as a person.
around a year after I met my fiancé I told him I felt suicidal (Though I never did any self-harm.) during my middle school years and he just held me and told me it was okay and that he would be there for me. So I think a real life partner should be able to accept the fact the fact that people can have these feelings. Even if they can't help they should be able to at least be there for you.
The scares would not be the problem for me. But I grew up with someone who had a mental illness and now I don't think I could handle your past without always wondering if you would ever fall back into it. Sorry I'm just trying to be honest