Even if we've confronted a concern in the best possible way, if we stay in the relationship, it's hard to tell if change has occurred and for what reason. It's like trying to repair a car while driving down the highway. You don't owe it to your friend to stay in the relationship. Either of you, short of the altar, may decide against the relationship. It's better to end the relationship now than to keep going and suffer for it!
If you end a relationship, do so with kindness and respect. Let your friend know that you have concerns, that you've given it thought, and that you believe it's the right decision for you. Share the concerns if your friend would like to know, but address them as behaviors, not traits.
Be prepared for a number of different reactions. You might get promises, begging, or anger from your friend. If you end the relationship now, it doesn't necessarily mean that reconciliation may not happen down the road. Be careful of setting up the other person or yourself with that expectation. The inevitable question arrives, "Can we still be friends?" This question is often an attempt by one to stay in the relationship. Many people slide back into their relationship because they were trying to be friendly; like trying to drill a new screw hole 1/8th of an inch from the original. Many times, the end of a relationship will need to be firm and decisive. You are not a terrible Christian if you decide to end the relationship with your friend!
If you do break off the relationship, give yourself the opportunity to grieve. You very well may be in love with that person, and even though ending the relationship may be the smartest thing you've ever done, it still hurts! Journal, identify your losses, and don't try to meet someone else too quickly.
Some of you might be on the doorstep of marriage- a month, a week, or even a day away from that lifetime promise. It would be easy to let potential disappointment from a fiancée, a parent, or the loss of a reception hall down payment keep you from doing what you know you need to do. My goal is not to break couples apart, but for couples to have a greater confidence in their decision to marry. If that confidence is not there, it might be the wisest choice you ever make to delay the wedding date or end the relationship.
Pray for God's wisdom and direction in your relationship. I hesitate to mention it, not because I don't believe in it, but because it's so easy to distort. Time after time, I've seen people continue past clear and obvious relational red flags because "God was leading them." God does lead and guide, but praying about it doesn't become a trump card that no one can question. Ask the Lord for His leading, but see if there are important red flags. Many times God's leading will be affirmed by the people around us who are also seeking His heart, but maybe with a tad more objectivity since they are not in the relationship.