But slowly, Dominick’s intimate and intense influence on Jessica began to reshape her long-held convictions. He did believe in a god but had no commitment to him. So when I learned they were sleeping together, I was disappointed but not shocked. Paul wrote in 2 Corinthians 7:1 that we need to “purify ourselves from everything that contaminates body and spirit.” Letting someone who doesn’t hold our convictions and beliefs into the secret places of our heart surely can wear us down and contaminate the good there.

“But it’s my chance to witness.” My friend Lacey used to talk about her boyfriend Zach as if she had a secret time machine hidden somewhere. She would say, “Once he gets saved, he’ll be the perfect husband.” She acted as if it were a given.

I didn’t really know what to tell Lacey, because I could understand where she was coming from. I once met a non-Christian girl I really liked and quieted my inner warnings by saying, “It will be fine. She’ll become a Christian eventually.” But was my chief concern really the status of her salvation? No, selfish motivations were at play.

Several years ago, a woman named Zen Lee explained in the Columbia Standard why she dated only Christians. “I do not trust myself to desire the right things or to have the right motivations,” she wrote. “Maybe 99 percent of the time the motivations behind missionary dating are impure:  a need for attention or approval, [sexual desire], desire for companionship, longing to be understood, or a savior-complex. Every Christian should be wary of the secret motivations of the heart.”10

And even if our motivations were purely about a romantic interest’s salvation, missionary dating is a pretty ridiculous strategy. First off, we can’t save anyone – no matter how hard we work at it. It’s God’s call whose heart to work in, not ours. Second, the basic premise of missionary dating is purposeful deception. Do we really want to trick or lure somebody to Christ using our love as bait? I hope not.

Worse than the ineffectiveness of missionary dating is that it actually does the opposite:  it hurts our own faith. Like Lacey, we can convince ourselves that everything will be OK once the other person changes. But typically, it’s we who change.

Women may be especially in danger of this trap. In 2000, syndicated religion columnist Terry Mattingly wrote about a study that looked at trends in living together before marriage. In the Journal of Family Issues study, researchers found that “deeply religious men” far less commonly live with a woman before marriage than nonreligious men. However, “deeply religious women” were just as likely to cohabitate as nonreligious women. Why?

“My theory is that women are willing to make sacrifices for their partners, once they have become emotionally attached,” said one of the researchers. “They’re willing to make compromises to try to hang on to the relationship. Men won’t do that. ... These girls are probably thinking, ‘He’s not perfect. But I love him and I can help him change.’”11

This is exactly why over and over the Bible warns us, above all else, to guard our hearts (Ps. 119:37; Prov. 4:23–25; Prov. 22:5; 1 Cor. 16:13; 2 Tim. 1:14). It’s better for me to not even approach a non-Christian than to tease hurtful motivations.

Of course, that’s easier said than done. Luckily, we aren’t alone. God can do mighty things through prayer. And he can also do mighty things through the people he puts around us. I try to take advantage of those trusted friends and family members by being open with my life so they can lend me truth and accountability. I try to be honest with them. And to ask them to look out for me and keep me in prayer. In fact, I have even given some loved ones specific permission to challenge me and question me about dating decisions.