However, the point I would emphasize here is that both these types of cheating can contribute to dissolution of the marital partnership. The marital partnership is the foundation of the marriage and it exists only between the two people who joined together. Infidelity does not necessarily mean there is no more love in the relationship. Infidelity does not always mean divorce is imminent. Often it signals the presence of other problems, which are too difficult to communicate. More often than not, the cheating behavior is about the "cheater" rather than the "cheated". For example, if you are unable to openly express your sexual fantasies to your partner and you decide to cheat sexually--- yes, cheating is a decision, then this is a reflection of your inability to express your needs. Along the same lines, if you find yourself "falling in love" with a third party, this is a reflection of your inability to emotionally connect with your partner.
Cheating is not the problem; it's actually the solution people engage in to resolve whatever problem they are having. I do not say this to negate the impact or significance of cheating, but I do want to emphasize that addressing the underlying problems behind the cheating behavior, is the only long term solution to it.