Religion doesn't really have any impact on dating, but it does come into play quite strongly if the couple get married. Once married the couple can have children and it is then that problems between mixed religious marriages can become stressful. Which religion is chosen to bring up the children in? Would it be the Father's religion or the Mother's?
Thinking of it this way means that we should consider religion before starting to date. It is a sad thing to get involved and fall in love with someone only to break up because of a difference in beliefs.