interracial dating: 跨种族恋爱 interracial marriage: 跨种族婚姻（不同人种的婚姻） interracial :不同种族

" interracial dating" in Cantonese, Chinese : 同外國人怕拖 “ Interracial marriage" in Chinese : 異族通婚

I don't think there is a certain way or "special" way in Chinese to say "interracial dating"and"interracial marriage".

interracial dating: 异族恋爱?(not sure about this) Interracial marriage:异族通婚/联姻

Interracial marriage:means marry with other Interracial people.like chinese marry with american. interracial dating :means have a realationship with other interracial people.its the former in marriage~