Depends on your governing documents. If your governing documents do not prohibit married couples serving on the Board, it is best to have an internal policy or resolution against it to avoid the appearance of impropriety and potential conflicts of interest. With that said HOAs often struggle attracting volunteers to run for and be elected to the board.

In the event a married couple is elected to the board from the same home/lot, Board votes should not be confused with membership votes. Each Board member (married or not) typically has one vote on any Board business. When it comes to general membership business, like annual meetings and elections, married couples typically get only one vote because their right to vote is linked to the one lot they own.  Again, read and understand your governing documents.