Far too often I hear of women hanging in limbo while Lothario tries to determine which lovely gets the prize -- him!
They're called "cake-eaters" and they're easily identifiable:
1. Indecision: "I just don't know what I want..." usually delivered in a high-pitched whine. Let him know that he can take time to figure it out. You just might be gone by the time he does.
2. Stringing you along. He'll offer you just enough hope to keep you hanging. Negative comments about his girlfriend. Wistful words about "missing" you. He might not be intentionally manipulative, but, if you go along with it, you ARE being manipulated. If you still want your marriage, it's tempting to play his game, hoping he'll come to his senses. However, it's healthier for you to insist on the marriage you want -- one that does NOT include another woman.