that this question is asked   implies that the   question is posed  to find out whether sex after marriage of their  respective lovers would work.

it depends on the  risk willing to be taken

 but in genral  if  it  is going to be  with someone who  married another  sex after marriage will not  work.

if it is for the person  who gets married   and starts thinking whethersex  will work in his own marriage  he should  have  either  endocrine dysfunction or erectile  dysfunction or psychological problems  for sex  not to work

 or she should  have  vaginismus or congenital   genital defects  or imperforate hymen  which may not make sex  work

  otherwise  it will definitely  work