Is he a good man?

My boss is a gentle man, I think. He never speaks loundly to anyone. Sometimes he is a very affable person and he is just 5 years older than me. When he stays with his wife and little son, that’s really sweet and enviable. So everybody thinks he is a good man, a good husband and a good father. But people are complex, and I totally can’t understand sometimes. After I know he has a mistress who is (at?) our colleage ,i really can’t accept it. I think he is not as good as before. Someone says that’s normal, many people can do that. Every time I see him, I think he is hypocritical. And every time I see his wife and son, I think they are so pathetic.
Nothing changed, just my feeling changed. Anyway,as a boss, he is ok. I try to treat him as before and I know I can’t judge a person by one thing. But, is that really normal? Everyone can accept it?

A few things- You could say "He is 5 years my elder." or "He is 5 years older than me." Anytime you talk about yourself, the "I" should be capitalized. Also, any time you use a comma or a period, there should be a space after it, not before. "It shouldn't look like this , It should look like this. Then the new sentence begins." I hope that makes sense. I am sorry about your boss. It is sad, but it does happen.