This question not seldom causes a lot of controversy, especially among Christians who are currently involved in a relationship with a non-believer since in this cases it is also connected with very strong emotions towards the boy- or girlfriend.
However, having this question unsolved and not operating in God's wisdom can cause us a lot of disappointment, grief, unfulfilled expectations, as well as broken relationships, divorce and especially and most importantly a loss of intimacy with God, of passion, commitment and single-mindedness.