Getting married is easy. Being married can be trickier. Here is some expert advice to avoid or correct six common mistakes that can cost a marriage, or at the least, weaken its foundations. Whether it's you or your spouse making these mistakes, taking positive action can make a big difference.

For instance, if you don't speak up for what you want, your husband is flying blind -- and not likely to deliver. And the way you talk about your issues may be making matters worse. And then there's the bedroom.

1. Being Too Quick to Please

Some wives are too willing to give up on what they want, says Susan Heitler, PhD. She is a Denver-based clinical psychologist and author of Power of Two, a marriage skills-building course.

Heitler calls it "appendage-itis," in which the wife is basically being an accessory to the husband, instead of being a full and equal partner in the marriage.

Some women tend to be "all about him" rather than all about themselves, as men tend to be, Heitler says.

"Usually, they're afraid it could make a fight or some unpleasantness, or they just think somehow, on a subconscious level, in order to preserve the relationship, they have to diminish what they themselves want," she says. The sense of helplessness leads to anger that eventually boils over, she says.

Her solution? Express your concerns rationally, whether about housework or parenting duties, or about not getting enough time with your husband or for yourself. He may like golfing on weekends while she may want him around for family time, for example. "If she spoke up, they might be able to work out a better arrangement," Heitler says. "Maybe they'd switch to a softball league in the summer where it would be a family event.''