Happily married couples usually credit love, tolerance, and devotion as the secrets to their success. But when a relationship goes sour, people often find themselves wondering what went wrong. According to experts, there are several common mistakes—from infidelity and neglect to communication breakdown—that can cause a once-loving partnership to end in a bitter breakup. Want to avoid the same fate? Read on as we reveal the top seven relationship-killers.

Love on the Rocks

These common relationship issues could sabotage your domestic bliss.

1. Arguing about money. It's often said that money is the root of all evil-and that familiar axiom may be particularly true when it comes to relationships. Although most experts now believe that money isn't the leading cause of divorce, a study published in Journal of Marriage and the Family found that 32.9 percent of divorced women and 28.7 percent of divorced men cited financial problems as a reason why their marriages failed.

2. Having an affair. Not surprisingly, infidelity is often an instant relationship deal-breaker. What may be surprising, though, is how prevalent cheating actually is. According to a survey by the National Opinion Research Center, 25 percent of married men and 17 percent of married women reported that they had been unfaithful. And sadly, only an estimated 35 percent of unions manage to survive an affair.

3. Neglecting your partner. All too often, couples simply assume that a healthy, happy partnership is a given. But good relationships require work, and not paying attention to your significant other is one of the easiest ways to alienate him or her. For this reason, experts say that couples who don't reserve "quality time" for themselves (time away from phone calls, kids, and other distractions) often pay a hefty price.

4. Failing to communicate. According to the Journal of Marriage and the Family study, communication breakdown was the number-one reason why marriages failed. In fact, 69.7 percent of women and 59.3 percent of men cited a failure to communicate as a reason why they'd gotten divorced. Experts warn that if even one partner has a tendency to withdraw, rather than to address and resolve conflict, it can put a relationship in peril.

5. Holding grudges. Chances are, you've heard the expression, "Never go to bed angry." As it turns out, this familiar piece of folk wisdom really is sage advice. Although it's important to stand your ground on serious issues, experts warn that holding petty grudges against your partner can result in resentment, stress, and eventually relationship breakdown.

6. Refusing to compromise. Compromise may sound easy, but many couples have a hard time balancing the necessary give-and-take of a relationship. The result? In some cases, a breakup or divorce. Remember, compromise is essentially the art of negotiation, meaning that eventually each party has to give up something they want for the greater good.

7. Being too critical, controlling, or needy. According to experts, excessive criticism, controlling issues, or neediness can all set the stage for a bitter breakup. If you or your partner is engaging in any of these bad relationship behaviors, it's important to seek counseling right away. These issues rarely go away themselves and, if unaddressed, can escalate to the point of no relationship return.