What makes it possible to have more than one lover at a time, emotionally and practically?

There have been a number of questions about friends with benefits lately, and people keep on insisting that you can separate sex from emotions. I think some people need to do that in order to have several lovers at once. However, I imagine there are people who could actually love more than one person at once. In other words, there are probably many different ways to make it possible to have more than one lover at a time.

Whether you’ve had experience with this or not, what do you think it would take to successfully handle more than one lover at once? What would you have to do with your feelings? What would you have to do with your logistics? How would it work, practically speaking? For example, how much time would you need between meetings with each lover, do you think? What other issues to you think you would have to deal with?