Find out what you can about the timeline of how and why it ended. In his discussions of his divorce, you should be able to see her side of the story at least a little and observe the habits of his that angered her.
(This lasts until their solar progression moves into Scorpio, at which point they become incredibly stubborn and empassioned themselves, but that is the subject of a different article entirely.) Libra men are a breed unto themselves.
They are the guys who dated every pretty girl in high school or college (or desperately wanted to), never managed to have their heart broken (or appeared that way anyway) and could charm the pants off of all their mothers at the same time.
People with several planets in Libra tend to be diplomatic, sociable and communicative.
People who were born when the sun was in Libra, are idealistic, fair-minded and alternately intense and blase (all that balance makes them express both sides of the spectrum from time to time). Not so much because they adore attention, like Saggitarians, but because they are naturally sociable and flighty, they know how to flatter, and they move quickly from one thing to another, not liking to dig too deeply or become embroiled in nasty and empassioned disagreements.
With the "slow it down warning" emblazoned on the relationship, let's look at the possible pitfalls your man presents.