I really don't believe that an affair outside marriage can last more than a few months without sex. The reasons for the same for men & women have to be looked at separately.

FOR MEN :

I really don't think that much reasoning or discussion is required. I have never seen a man claim that i am having an affair for emotional support that i don't get from my wife. For men, sex is a part & parcel of an affair. Without sex, an affair won't last. A good man may provide all the emotional & financial support to the woman involved to the best of his ability but the man is definitely looking for some kind of sexual gratification in return. If that is not made available, the man will not be interested for long.

FOR WOMEN :

Women are complex creatures and most don't show what they actually want. Societal pressures / our culture is the primary reason for this behavior. Thus women can't be blamed for the same. The reasons for a married women entering an affair may be :

1. Hope of some kind of emotional support which is non-existent.

2. Seeking pride, self worth, attention, time & sympathy

3. Out of sheer boredom

4. Seeking financial help for her own family

5. For sexual gratification, specially in cases where husbands are either not too keen to have regular sex, for whatever the reason it may be, or are unable to satisfy the wife sexually. Age difference can be a big problem. Out station jobs ie. absence of husband for long duration can also be a reason.

The problem is that can a married women find a guy who will only provide emotional support? If the guy is young, he is looking to experiment. Married women are the easiest targets. No young guy would be interested in a long term relationship with married women for obvious reasons. As for a married man, if the guy was so patient, nice & loving that he can provide good emotional support, his marriage would have been intact and he wouldn't be looking for another married women. 99.9% guys are looking for sexual gratification and if they get what they want, they may extend emotional support. A married women if clearly states that she will never have a physical relationship outside marriage and is not ready to talk about sex, will fail to find any guys. The guys who still go for such a lady are either overconfident that they will be able to change the lady over time or are desperate to have some opposite sex in their lives & have no other options available to them or are happy even with adult chatting (if the lady agrees to the same)/ normal chatting to kill / pass time. I think sex is a part & parcel of such relationships.