After an ex cheated on me, I went on a dating rampage and ended up dating 6 guys at the same time(not sleeping with them). That was my max, and I don't see myself ever trying to be a player again..
Many years ago, I had three girlfriends at the same time. It was exciting at the time but damn was it exhausting. I was only able to keep it up for a couple of months.
Two - we're a poly triad, so we all date each other. I enjoy it a lot. I don't think it's wrong as long as all the people involved are comfortable with it. It's only cheating if it's an action that breaks relationship boundaries, and you can design those boundaries with your partners however you want.