MLC? Not likely. Immaturity? For sure! You have a little girl there who is not growing up. She has fantasies of Prince Charming and happily ever after. She got married and it wasn't happily ever after, so she has to look for a different Prince Charming. Who knows if and when she will come to the realization that life is not fate. Things are not 'meant to be'. That adults make choices and build their lives. You can't control everything, but you also don't swing in the wind waiting for life to show you what's meant to be. Unless she grows up, she is likely to keep repeating this behavior. There are examples of wives on this board with teenage children doing the same thing.
There are 2 Retrouvaille groups in Australia. If she drops OM completely, and goes to one of these weekends with you, she might learn something about marriage, love and commitment. See http://www.helpourmarriage.org. for locations and dates. Your wife was not ready for marriage. She is still dating.