homewrecker       
noun [ C ]  disapproving uk/ˈhəʊm.rek.ər/ us/ˈhoʊm.rek.ɚ/
 破坏别人家庭(或恋爱关系)的人
someone who is responsible for breaking up a marriage or relationship
  He denied he was a homewrecker, despite his fling with Sarah being blamed for the collapse of her marriage. 他否认自己是一个破坏别人家庭的人,尽管他与萨拉的风流韵事被指责是导致她婚姻破裂的原因。 
 Her reputation as a potential homewrecker seems ludicrously misplaced. 她可能破坏别人家庭的名声似乎大错特错了。 
 - More examples
 - I don't want to be seen as a homewrecker - but I don't want to give up on a potential soulmate either.
 - I am really upset about it because I am being portrayed as a homewrecker, when it simply isn't true.
 - By now you've probably got me down as some hard-hearted homewrecker, but my behaviour shocks me as much as anyone else.