It’s An Ugly Truth: The 8 Most Common Reasons People Cheat
Their current partner would fall apart
If left, the current partner would become deeply depressed, would have a mental breakdown, or might even do something to harm themselves or others. That is a very tough spot for the emotionally stable partner to be in. But, everybody wants happiness which is why someone with such an unstable partner, might look for love elsewhere, while still being a rock for their partner.