I've written several books on relationships. I've spoken on thousands of radio and television shows about relationships. Two years ago I founded eHarmony.com, an online service dedicated to helping singles create better relationships.
I also spent 35 years as a practicing psychologist dealing with, among other things, relationships. You're probably seeing a pattern. My entire career has literally been immersed in the study of relationships and, remarkably, ALL of this research and experience has led me to one undeniable fact:

Similarities between two people are absolutely critical to a long-lasting love relationship.

It is a simple, eternal truth. In this series of articles I'm sharing with you the list of similarities I believe are essential if a relationship is to become successful.

In our previous installment we noted the first three similarities:

1. Spiritual faith
2. Intelligence
3. Ambition

Now we're going to examine four more important similarities to search for in potential relationship partners:

4. Personal habits. If one person regularly gets things done and the other person is a procrastinator they're going to have a lot of trouble getting along together. If one person takes a shower every day, and the other person skips a shower every once in a while, they're going to have some difficulties along the way. What are your personal habits like? Are you always on time? Then you may get tired of a person who's regularly tardy. Personal habits are a critical part of a couple's relationship. It's important that you make sure you have a lot of similarities in this area. 

5. Social interests. How much interpersonal involvement do you want to have? It's important that you find someone to live with who wants to have about the same amount of social involvement. I know some people for whom similarity is simply not one of the things they have in the area of social interest. The woman loves to be out and among other people a lot. The man loves to stay home and watch television all by himself. They live a life that is filled with resentment on both of their parts. And they grate on one another every time the possibility of social involvement comes up. She wants to go and is resentful that he won't go. He doesn't want to go and is resentful that she's going. Social interest needs to be carefully thought through prior to any sort of commitment.

6. Parenting interests. If you want to have children it is absolutely critical that you check out very carefully whether the other person wants to have children too. And it's not just whether you want to have children or not, but you also need to check out when you want to start having a family. If he wants to wait ten years and she wants to have a family in the first couple of years of the marriage, that's a critical difference that's going to cause a lot of resentment. If she wants to have two children and he would like to have five, that's going to cause a problem too. And by the way, it's also crucial sometimes, to check out what the other person's ideas are about how you raise children. Make sure you have similarity in that area.

7. Financial Management. Money is so central in our society-so crucial to our life together. When she wants to spend a lot of money and he doesn't, that's going to cause him a lot of resentment toward her. When she wants to spend money and he doesn't let her, she's going to feel repressed and constricted. Some couples don't deal with finances until after they're married and they make a big mistake, in my opinion, because while financial management may work out just fine over time, I've seen some marriages that were in real trouble because there wasn't similarity in this area.

I have talked with singles who feel like discerning this information in the course of dating makes the evening feel like a job interview. However, if you listen intently and arrange the night so most of it is spent in conversation it can be easy to learn where a person stands on these important issues.  I am not suggesting that you bring a list of questions that you read from during the date. I am suggesting that you make this knowledge a priority. Your happiness and the success of your future relationship depends on it.

The eHarmony Research Library is a branch of eHarmony.com(tm), North America's most successful Relationship Building Service. Our precise technology searches a database of 500,000 persons to find truly compatible matches. Then, eHarmony's guided communication system helps you meet and get to know each other in an appropriate, in-depth manner.  Click HERE to learn more about eHarmony.