It's not unhealthy or bad to prefer to run content with certain people; personally, I vastly prefer to have my statics whm healing me since we work so damn well together (7 months of raiding do that). I don't have issues running on my own (outside of getting paired with people who just will not try abd are super lazy)

However, it is bad when you are distressed or so unhappy running things without your partner. That's the problem. Sure, disappointment is normal if you can't for things, but being unable to play without them? You have a problem