How do I keep from being friend zoned?

I've had this issue in the past. I was dating a guy who would text regularly but dump his problems on me. Like of course I'm there to support and listen as a partner! But that relationship turned into just being his best friend and nothing more romantic. If his job is terrible and he needs to vent, I'll listen and advise. But how much is too much? I don't want to be treated like one of the guys again. I get that he's stressed but I have a feeling it's going that way. I'll keep listening and whatever happens, happens!