Whether you adore your partner's parents or barely tolerate your in-laws, your rapport with them can have lasting effects on your own romantic relationship. In fact, according to new research, it could even predict your odds of staying together over the long haul.For the study, which will be published in a future issue of the journal Family Relations, Terri Orbuch, a psychologist and research professor at the University of Michigan's Institute for Social Research and author of "Finding Love Again," followed 373 couples who were newlyweds in 1986. She asked the men and women to rate how close they felt to their in-laws, on a scale of one to four, and then tracked their relationships over time.After 26 years, Orbuch found that when a man reported having a close relationship with his wife's parents, the couple's risk of divorce decreased by 20%. Yet women who said they had a close relationship with their husbands' parents saw their risk of divorce rise by 20%.It makes sense. A lot of men (myself included) look forward to the idea of gaining a new family when they get married. It's a chance to have a "mom" and "dad" without many of the entanglements that they have with their own parents: They can enjoy a ballgame or a home-cooked meal without feeling judged or hassled.Plus, guys are less likely to worry that their in-laws are interfering in their relationship. Men tend to identify as a provider first and a father and husband second, so they don't find their in-laws' input particularly threatening, Orbuch says."Close in-law ties between a husband and his wife's parents are reinforcing to women and connect him to her," she said. "When a husband gets close to his wife's parents, this says to her: 'Your family is important to me because I care about you. I want to feel closer to them because it makes me feel closer to you.' And of course, that makes us as women feel really good."Being a daughter-in-law can be much trickier. On one hand, a woman may be more likely to form a bond with a man's parents when she wants to change something about him or get him to agree with her about an aspect of child-rearing -- essentially, trying to get his parents on her "side." This closeness can result in a unified front against the husband and, as you might imagine, is apt to infuriate him.Yet a tight relationship with the in-laws can also backfire for many women: Closeness may give a mother-in-law a greater sense of access and ability to cross boundaries and meddle, which can seem threatening, particularly if a woman feels that her in-laws are interfering with her identity as a wife and mother.Orbuch says that in her long-term study, she found in-law ties to be very stressful for women."If women are close to their in-laws, especially early in marriage, this interferes with or prevents them from forming a unified and strong bond with their husband," she said. "Also, since women are constantly analyzing and trying to improve their relationships, they often take what their in-laws say as personal and can't set the clear boundaries."Here are some tips for getting along with your in-laws and strengthening your relationship with your spouse.Get to know them. Don't limit face time with your in-laws to the holidays, when everyone may be feeling more stressed. Spend time with them socially on occasion, and get acquainted with them as people. This is especially important if you're a man, because caring for your wife's parents shows her that you care for her, too.Know your limits: If you're a woman, let your in-laws know that you want a loving relationship with them, but set some boundaries. Just because they're your husband's parents doesn't mean you should tell them everything.Maintain a careful distance: This is especially true if you have kids. Don't let in-laws use their desire to visit with your children as a way to invade your life, and don't allow them to critique your parenting skills. Just because you have given them grandchildren doesn't mean in-laws should have an open door at all times.Keep things cordial. Don't insult your in-laws, even behind their backs. If you have an issue with them, talk reasonably to your partner. Even if your spouse complains about his or her parents, stay quiet. No one likes having their parents attacked.Put your relationship first: Defend your relationship against outside threats -- even if that means your in-laws. I meet so many couples whose anger stems from one or both partners feeling undefended: "He lets his mother walk all over me!" "She never stands up to her father, or stands up for me!" If this kind of behavior persists, it can poison a marriage. Instead, make it clear that you expect your spouse to defend you without lashing out or being passive-aggressive.Remember, you married your spouse, not his or her parents. But you can make the holidays -- and every day -- a bit brighter by forging realistic bonds with them.