Anyone that’s been married for more than five years knows that even the strongest marriage can have its ups and downs. During some of the "downs" the two of you have experienced together, you or your spouse may have wondered: "Did I marry the right person? Can I spend the next 20 years with them?"

Then, for whatever reason, it passes and you feel you love and appreciate your spouse more then ever and the two of you are a perfect fit… until the next downturn.

Having worked with couples for more than 20 years. I want to preface my observations by stating that all relationships require care, selflessness, accommodation, deliberateness and real commitment.

However, after years of practice and experience, I cannot overestimate the importance of compatibility and the right attitude. Compatibility is a very complex concept, which is at the heart of this subject matter. There is no simplistic way to define it, accept that we all know when it is there.

Opposites Attract

Often times, we are attracted to those who are opposites of ourselves. We all have what’s called a "completion fantasy," i.e. "you and I are halves of a perfect whole."

Unfortunately, as most relationship therapists know, what attracts us is also what creates the biggest conflict in a marriage down the line. So the question is: Do you want to be the kind of person you have to become to be a part of this whole? Do you want to grow in the direction you need to grow to be comfortable in this relationship?

For example, I am currently working with a couple that’s been together for almost four years. They are relatively young—she is in her early 30s and he in his early 40s. She is what I would call a "delicate flower" and he is a fairly loud, assertive (almost aggressive), opinionated guy.

When they first met, she was attracted to his aggressive style and know-it-all attitude because she felt protected by him. Now they are in couple’s therapy because she has shut down and feels intimidated and uncomfortable with his aggression. There is no thread of physical aggression here. She just feels turned off by his loudness and brashness.

In order to make things work, he needs to become softer with her and she needs to be more assertive and let him know how she feels in those particular moments with him.

Are You Envious of Other Couples?

Another sign of a troubled marriage is when you chronically look at other couples and feel envious of them. Now, every once in a while this happens to every couple—you see a couple that’s very happy in a particular way or you like something about their relationship and you wish yours was more like that.

But when that is your experience, more often then not, it may be a sign that your marriage is in trouble. Pay attention to what triggers your envy or why you're wishing that it were you. By doing so, it will point to what you are not really getting. It’s important to communicate your needs to have more of those needs met.

In order to have a good marriage you have to be able to put your ego aside and give in. I think keeping one’s ego in line is one of the less obvious purposes of a marriage. You have to consider what the other person wants and needs and not feel resentful about giving that to them. Once the two of you are able to do this, your marriage will evolve in a positive direction.

Irina Firstein is a relationship therapist in New York City for over 20 years. She works with individuals and couples. You can visit her website at www.psychotherapist-newyork.com.