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I think that they can work out if both parties are involved and communicate about it. Of course relationships like this are not for everyone, but they can work out. I think the thing about it is that both people have to want it. Both people have to know what they expect out of the relationships and what boundaries they want to set. They have to talk about what they want to happen with the relationship and what they like and don't like. And obviously they have to be willing to make the effort to keep the relationship going strong.