(Follow up question to the contacting the ex question.) How much do I need to consider the feelings of his spouse in this situation?

This question was prompted by a question johnsblond asked in that thread. She asked me to consider the feelings of his wife. But why should I?

I knew this guy a decade before they even met. He was my 2nd closest friend for years before we even got together. She had major problems with him talking to me when they were first dating; they weren’t even in a relationship yet. I see this as petty, and I feel no reason to encourage it. This is why I feel he has not told his wife he has contacted me. But why should this be my concern?

I have a feeling this question might offend some, but please don’t bite my head off. I have always had problems understanding women, and I must admit that I can be selfish.