Is it right to evolve a friendship with the opposite sex into a "close" one when married? To the point of chatting with him/her first thing when you wake you up in the morning and the last thing you do at night when you don't even do it with your spouse? I call that cheating. What do you think?

Hmm. .....well! See it happens in almost every relationship when there comes monotony in married life. And if there is no self moral policing from others and from oneself everyone would once in their married life would do this if it is called cheating or whatever. I think it is just a temporary attraction towards someone else because you are bored in your marriage. It is just fine but make sure that you set your boundaries because if you will not then you will feel guilty when you will come out of this temporal phase. So, I guess do not feel guilty and enjoy it but you must set your limits and do not go beyond that.