I had a cousin in the Air Force that got hitched seven times. Never once learned his lesson. He just married every gal he dated, and then he'd get divorced a few years later.
He had a kid with his first wife, then he divorced her because she got knocked up by another guy. When that second kid was an adult he had a DNA test because he looked just like my cousin, and it turned out to be his kid all along. They became roommates for a while after that. The second wife made him get a vasectomy, and the fourth wife made him get it reversed so that they could have a kid together, which they did. Then he must have gotten another one because he burned through three more wives after that without knocking any of them up.
That's the most extreme case of stacking exes that I know of.