"And Itzchak brought her (Rivkah) into Sarah his mother's tent, and he married Rivkah and she became his wife, and he loved her; so Itzchak was consoled after his mother." (Bereshis 24:67)
What is love?
I can tell you what love is not quite easily. Love is not what is called "love" in popular culture, in the movies, television, books or magazines. What this is can be more properly called "lust". It's an odd injustice that the English language doesn't allow "lust" to be used grammatically like "love". If it was possible for people to tell each other "I lust you", the phrase "I love you" would probably be used a lot less often.
Simply put, the difference between lust and love is that the former is based on feelings of selfishness while the latter is based on selflessness. Lust is a feeling of desire evoked in the lustful person. In a relationship between two people, lust is the desire one feels to be with another person, to share his or her company, because doing so gives that one a feeling of pleasure. The feeling the other person (the "target") has for the one feeling the lust (the "luster") is quite irrelevant (hence, in popular culture, one can be in "love" with a movie star, athelete or rock star one has never met). That doesn't mean the target can't be an engaging part of the relationship. The target may also lust the luster, in which case a strong connection can develop. Indeed, these relationships can be quite pleasurable and intense. After all, if the luster wants to get "more" from the target, he or she will do things that the target finds pleasurable since the target will then reciprocate, increasing the luster's pleasure.
The danger of this kind of relationship is that it is based on novelty. Like any particular pleasure (excluding chocolate, of course), repeated exposure tends to dull excitement and feelings of enjoyment. Listen to the same song over and over, watch the same movie over and over, and the feelings of excitement and interest dull over time. This is no different when two people are in lust. Whether it's the duration of time together, real-world pressures interfering in their lives, pregnancy and the subsequent changes to the woman's body, something happens to dull the lust and if there is no true love to replace it, the realtionship comes to a shuddering end.
In short, lust is about a person making his or her needs the most important personal priority.
Love, on the other hand, is quite different. It is not a coincidence that the Hebrew word for "love", AHAVAH, has the unusual verb for "give", HAV, in the middle. If lust is about taking, love is about giving. Love can best be defined as a state in which the other person's needs are the most important personal priority.
In recent Jewish sources, the Michtav Eliyahu discusses something very similar to this. According to Rav Dessler, zt"l, in a realtionship one can be a giver or a taker at any one time. For example, the husband comes home after a long stressful day at work. He needs to "take" emotional comfort from his wife. His wife gives it to him. The next day he returns home in better shape but his wife has had a horrible day. Now she becomes to taker and he the giver. Because of this reciprocity, because each partner sees the other person's happiness as their own personal priority, the relationship works and thrives.
Is this not something the Torah was hinting at with the verse at that beginning of this post? Recall that the marriage of Yitzchak Avinu and Rivkah Imeinu was arranged by Avraham Avinu's major domo, Eliezer. Forget three dates and meet the parents, these two met the day before the wedding and the parents never met each other at all (one must suggest this is a hint of the superiority of their culture to ours)! Even when they meet, Yitzchak does get a good look at his prospective bride because she veils her face.
Yet what happens? "And Itzchak brought her (Rivkah) into Sarah his mother's tent..." Rashi's comment on the verse is: "And he brought her into her tent and she was made into an image of Sarah his mother. That is to say, 'and behold, she was Sarah his mother', for the whole time that Sarah was there a candle was lit from one Erev Shabbos to the next, and the dough was blessed and a cloud hovered over the tent. When she died, these things ceased and when Rivkah came in, they returned."
One can see from this Rashi what the core Jewish principles are for forming a relationship. It isn't lust, the physical attraction and the superficial characteristics that create a deep, permanent bond between two partners. It is shared characteristics, ideals and priorities. Far from "opposites attract", it is two people whose priorities are so similar so that giving to each other is natural and without any difficulty that will last together for a long time.
It is because Rivkah's tent was the same type of home as Sarah's, so that it could be said that things were just like when Sarah Imeinu was in charge of the domicile, that Yitzchak could work together with her. And because of these shared ideals, "he married Rivkah and she became his wife". A couple have a great wedding with 100's of people in attendance and a sweet table to end all sweet tables, but they can still fail to develop a good marriage. The Torah tells us that Yitchak and Rivkah not only had a good wedding but they continued on from it, building a relationship on the values of Avraham Avinu that they both shared. And as a result "he loved her". Yitchak Avinua's greatest pleasure was pleasing Rivkah and hers was pleasing him. Imagine a relationship in which giving is what is the most enjoyable thing instead of taking. Can the happiness ever end?
Finally, "so Itzchak was consoled after his mother". They say men marry their mothers and maybe this is where the idea came from but that is not the intention of this statement. It is only after Rivkah has demonstrated that she is a worthy inheritor of Sarah, after she and Yitzchak develop an unbreakable marital bond and reproduce what Avraham and Sarah had, that he is consoled after Sarah. Yitzchak's life was not without purpose (more on this in Parshas Toldos) and with Rivkah, he was able to fufill that purpose. Sarah, in this sense, was no longer dead and therefore the holy mission of the family could go on.
As mentioned above, our dominant culture thinks quite differently than this verse does. May we all have the strength to gaze upon our loved ones and make their priorities ours, to make sure we utilitze the "hav" in "ahavah".