I find the word abuse to be very limiting. because sometimes, things in a relationship can be unhealthy, destructive, and hurtful, but labelling at as "abuse" seems extreme. And actually, a friend of mine who works at a women's shelter says that because of the stigma of words like "abuse", "victim", so and on so forth, almost every person thinks to themselves "I wasn't abused...abuse is X." "At least s/he didn't hit me." "At least s/he didn't hit the kids." "At least s/he didn't rape the kids." So on and so forth, there's always a higher level that is "abuse" when theirs is not.
I'd say if either party feels controlled, undervalued, or afraid, it could constitute as an unhealthy relationship. Sometimes, both partners feel that way. I think instead of fearing the "abuse" label, it's important to simply be open and understand the gravity of your partner's concerns. Take them seriously, talk them through with as much honesty and as little defensiveness as possible. Say what you mean, and let your actions reflect what you want to say (for example, sometimes people engage in bad/controlling behaviour to send a message to their partner - rather, it is better to simply express honestly and respectfully and have enough trust to work through the issues).