Casual vs. committed

Let me first state that I am a decent person. I have just gotten out of a year-long relationship with someone. I don't want to be in a relationship right now, but I do enjoy female companionship. Let's "hypothetically" say that I am currently dating a few women. It has been casual with all of them and I haven't given any sign that I want any more than that.

I have recently been asked by two of them, not at the same time, "Where is this going?" I respond in the most honest way possible, "I'm not ready to be serious, I'm enjoying the single life." Both of them have gotten pissed that I have gone out with other women while we have gone out on a few dates. Let me reiterate that I have been completely honest from the start.

My question is, am I in the wrong and how long can a relationship stay casual?