neil if you say you didn't feel abused, then you didn't feel abused. That's ok, no-one is going to argue with you about your own feelings.
I wonder if this thread has made you think a little differently about your behaviour as a reaction to your wife's sulking? You had sex against your wishes. Ok, it was probably not forced on you but, in your own words, you did it to keep the peace.
I felt I couldn't turn her down because I knew she'd sulk for days
Whilst you may not have felt abused, her actions were abusive. Do you see the difference?
In most situations abuse starts at this very low level, where the person being abused questions their own rational thinking and doubts themselves. This is how people find themselves in abusive relationships without really understanding how they got there, or how their normally wonderful partner can be considered abusive.
If the abusive behaviour is tolerated, it will often escalate. But not always. Sometimes it stays very low level, with an imbalance of power within the relationship and people just learn to live with it.