It's often been said that we don't marry a person, we marry a family. While this may seem like an old-fashioned adage, anyone who is married or who has been married will tell you: it's the truth.

When couples are dating, a future spouse's family often doesn't play much of a role in the relationship. The in-laws-to-be may live in another town or another state, and the focus is often on the first flush of love and the excitement of planning a life together.

But how to handle the in-laws is tricky territory for every couple — and one that doesn't fade after the wedding.

Dr. Susan Forward, author of the book "Toxic In-Laws," warns that just like money, how to deal with each other's parents is territory that needs to be explored before couples tie the knot.

"Nobody talks about this stuff," said Forward.

Here are the five top topics that Forward recommends couples cover when it comes to navigating the relationship with the in-laws:

1) Whose team are you on?

This question needs to be approached with honesty and pragmatism. What is the nature of your future spouse's relationship with his or her parents? How will you fit into the relationship?

"Couples need to find out from their partner how much loyalty, obligation and guilt is involved with their parents," Forward said. "Unless the partner, the adult child of the parents, is absolutely willing to put the person they're going to be marrying first, things are not going to go well."

Why? "Because there are going to be 100 times when the husband or the wife is going to be forced to choose between family and spouse. They really have to support and back up their partner," she explained.

2) If your parents don't like me for some reason, what are you willing to do about it?

What this question really means is: "Are you willing to protect me? Can I feel safe with you?"

It's important to ask this question honestly, Forward said, because people often feel abandoned when they marry.

"Later, they'll ask their husband, 'Why didn't you say something when your mother said my hair looked awful?'"

3) What happens when I'm not there?

When a husband or a wife visits with their parents and their spouse is not present, what is being said about the other person?

There has to be a comfort level for both spouses in this situation, Forward said. The spouse needs to be confident that that there will not be a lot of backbiting when he or she is not around.

4) What happens when children come on the scene?

The crucial question here is whether or not the husband and the wife's parents are going to recognize the couple's wishes when it comes to child rearing.

For example, will the parents of both spouses agree to respect the way the grandchildren are being raised?

If the husband received occasional spankings while growing up but he and his wife have decided against physical punishment, will the in-laws respect the couple's decision, or will they spank the grandchildren anyway?

This may be an extreme example, but it's just one of the problem areas that arise when children come into the picture.

5) How much time are we going to be expected to spend as a couple with your parents?

It's natural for both husband and wife to prefer their family to their spouse's family — but it's important to communicate in advance about how much time each partner expects to spend with his or her parents.

"Some people have a ritual where they're expected to spend every single Sunday with the in-laws. Is the future wife or husband willing to compromise at one Sunday a month?" Forward asks.

In her work with couples, Forward finds that many of the men and women who wind up with in-law problems subscribe to fantasies that don't mirror the reality of marriage. They think as soon they're married, the in-laws will change or once the children come, things will be different. These are not realistic assumptions.

Instead, Forward offers this down-to-earth advice: Your in-laws don't have to love you. They just have to treat you with courtesy and respect. Keep your expectations low.

Moreover, people who have lost a parent or come from a difficult family often think they will be getting a new, better family. That's not true, cautions Forward.

"Don't go into this with your eyes closed," she said.

A Few More Tips

All of Forward's advice makes sense, but how does it work out in the real world?

Maureen Pallotta from New Rochelle, N.Y., usually talks to her mother-in-law Maria Pallotta once a day, and even considers her a friend. How does she do it? By keeping the in-law arrangement in perspective.

"Look at it as an older person who could be helpful to you rather than this person who is going to dominate your life. The bottom line is you have to be respectful of who the person is. It's their baby. It's not all about you," Pallotta said.

"FOX & Friends" anchor Steve Doocy, author of the bestselling book "The Mr. & Mrs. Happy Handbook: Everything I Know About Love and Marriage," said learning to co-exist with your-in laws is a must — or suffer the consequences.

"You must find a way to get along. Otherwise, you are doomed to a lifetime of popping Tums."

Click here to read: Mr. and Mrs. Mom and Dad: What to Call the In-Laws