An astoundingly high rate. In Asia, the percentage is lower, but that doesn't mean affairs don't happen, and that it could never happen to you. So it won't hurt you to call each other for a few minutes on the mobile phone and just say what you're doing. In a relationship that isn't working out well, intimate touch is something that stops happening. If you notice your lover is kissing you less, hugging you less and touching you less, then take action to rectify the situation.
Communication is something that breaks down after a while.
Make the effort to find out who their colleagues are, who their bosses are, what they like and not like about their colleagues, their friends, what their hobbies are. Ask questions, and you'll get responses, which will lead to a pleasant conversation. After you've asked, listen. Listen is not the same as hearing. As John Grey pointed out in his Mars and Venus series, men tend to shut down and stop communicating in order to deal with stress.