Why do men cheat on their wives and then dote on their wives to the "other woman"?

i'm not getting the logic...i'm a miserably married woman and i joined a website that is geared toward other mutually miserable married members...i meet a fantastic male friend...we been talking and texting for 2 months now and it was his wife's birthday yesterday and he told me friday, saturday, sunday and yesterday about her birthday..so today, i told him that him and i aren't in the same place in our marriages and i told him that i can't continue to deal with him with the way he feels about his wife...if he loves his wife enough to mention her birthday 4 times to me and to plan a dinner with her, then what is the point of dealing with me?...he didn't noticeably take offense but he did say that him mentioning and caring about his wife's birthday doesn't change the fact of how much he enjoys our time together...that is bull to me...what do you all think?...yeah, yeah, i know i'm wrong for cheating in the first place but like i said, i'm miserable, sexually, mentally and emotionally in my marriage but i won't deal with men that are content with their wives...i feel like that is messing with a happy marriage and i won't do that...the guy doesn't see eye to eye with me but it does make a big difference to me because if someone is miserable then we have each other to confide in but if the guy is happy, why bother?...