5e Cross species Marriage

so im running a homebrew campaign right now, where my players are commited of crimes they didnt commit and need to escaoe and clear their names. and two of my players are engaged OOC and i wanted to make their crime tie in together. there is a half orc paladin and a drow monk. i want thier "crime" to have something to do with their relationship for each other. marriage is what i thought of originally but i dont know what recource to look in for cross species marriage, cultural customs, religous aspects, and outside views from a third species? can any one point me in the right direction?

From Roll20 Code of Conduct: Intended Use The Roll20 Forums exist to discuss topics directly related to the use of the Roll20 program. Anything that more fittingly could be discussed on another website SHOULD be discussed there. Honestly, I think your question would be better suited to enworld or reddit, sorry.

funny i thought "s[specific use" kind of applied to a specific situations. in a game. played on roll20. my mistake thinking to use the forums to get the opinions of other people playing the same style games. 

Sorry, as Matt W. said, the Roll20 Forums are for Discussing Roll20, not game topics, with the only exception being getting those game topics working on Roll20.  Such things are better discussed on other sites dedicated to those things.