This gives me the big ICK.
It also turns me off when a man has had multiple serious girlfriends because in my mind I will always be thinking about how he must have flattered all of them with sweet words, gifts, plans, promises, and all sorts of attention as if she was the love of his life. I will be thinking, "wow, all these things he said to me he said to another woman." He even thought she was the one. This is why I dislike Ted Mosby from "How I Met Your Mother".
I will view him as lacking self-discipline. Like really? You thought you were in love with each girlfriend at the time that you were with them? Made them believe that they were the one only to be discarded in the end? Sounds like you used them to get access to them and then dumped them.
But for some reason if a man is divorced it doesn't bother me as much. A man showing love, affection, to his wife, is him showing commitment and investment in his marriage. He did those things obviously because it's expected of a husband. But if things didn't work out then it just didn't. Not a red flag unless he was the one who sabotaged it.