Women across the world complain about their partners saying, "He never talks about his feelings" or worse, "He is so insensitive - he turns around and goes to sleep even as I am crying!" Although there are exceptions to every rule, it is generally said that women are more emotional and communicative while men are practical and solution focused.
Men have often been blamed for their lack of emotional expression - barring anger - and most women believe that their marriage or relationship would be far more fulfilling if only the man would be more responsive and expressive with regard to emotions. It is true that women are far more in-tune with their emotions and perhaps are able to express the same with greater ease, but it would be presumptuous to believe that men do not have emotions. After all, they are just as human and have the same emotions. So then, why are so few men able to respond and express emotionally?
There may be several contributing factors, the first of which is something that we all have often heard and blamed: socialization. In most cultures, boy children are told "boys don't cry" and are given other similar messages. A growing boy learns that emotions which are "weak" such as fear, sadness etc. must be avoided and learns to express all these emotions manifested as anger. Anger is one of the few emotions that gives one a feeling of power and control and hence is an "acceptable" emotion for men.
Another factor is difference in problem-solving; when a woman is upset she is likely to feel better after discussing it with a friend, even though there may not be a "solution" that she has arrived at. Men on the other hand are always looking for solutions - so when a woman is complaining to her husband about her terribly mean boss, he is likely to respond in a way that provides a solution, such as perhaps, "If he is so annoying, why don't you quit / look for another job?" Typically this response would be the last thing a woman is looking for at that time, because what she wants is some understanding, acceptance and discussion. The time for solutions is later; right now she wants to be heard!
Men on the other hand do not believe in discussions and would discuss a problem with a friend only when they need help or a solution and hence he is trying to do what he thinks best when he offers the woman a solution!
Apart from the above, research suggests that there is another reason why men seem to avoid emotions - a popular research study compared the responses of young boys and young girls to recordings of babies crying. The initial results showed that the boy children switched off the recordings much earlier than the girls, and hence appeared to be "insensitive" to the pain of the babies in the recordings.
However, on further investigation it was revealed that the boys showed much higher levels of stress on hearing the babies crying, than the female counterparts. The boys had higher levels of stress hormones such as cortisol, showed higher blood pressure and pulse rate - basically proving that the recordings of the babies crying actually affected (physically) the boys more than it affected the girls. Men are more sensitive to emotions and hence are more likely to avoid it, as an instinctive survival mechanism, by either getting away from the situation physically (walking out) or psychologically (shutting himself off or going to sleep). Ironically then, men are perhaps the "weaker sex"! In fact, old men are much more likely to die soon after the loss of his partner than an elderly wife if she loses her husband.
The reason could be that women are "programmed" for motherhood and hence are more able to deal with the stress of emotions, whereas men, who historically had the role of the hunter-gatherer actually learnt to put away these emotions in order to be successful at his job of hunting and gathering food for his family back in the cave!
Having understood the possible reasons that may make a man seem "insensitive" it is also important to make the required modifications in interactions, which can make not only marriage, but all interactions between the genders more fulfilling.
For Women
Keep in mind that emotions can be overwhelming and extremely stressful for a man and hence he might be avoiding it to protect himself. Of course, some discussions cannot be avoided and hence while discussing important aspects that you want him to pay attention to, keep the emotional expression to the minimum. Instead of saying "I feel..." or indulging in other overt displays of emotions such as crying, it would be better to keep the discussion action oriented by saying something like "It might be a good idea if we do such-and-such about that".
Also, make sure you have plenty of female company to discuss and ventilate your emotions with!
For Men
A man must also realize that women need to off load sometimes, and when his partner is worried or upset about something, he can ask her if she wants to talk about it. And of course, it would be important to resist the urge to "solve" the problem, especially if she hasn't yet expressed herself fully!
And of course, practice makes perfect, so keep practicing - women at avoiding emotions in discussions and men need to practice dealing with emotions!