When does it become cheating?

I should start with an apology for being away for so long. I’m sorry. Really, there are no excuses. Nothing besides sheer laziness….that’s it… I’ve been too lazy to post anything….procastination does suck!
That said, Happy New Year again. Hope you all had a lovely Easter and… (that’s it, right? There’s been no other major holiday, yeah??)
Now to the reason I’m here WordPressing on my windows phone in the middle of a ‘meeting’. Spent a good part of my lunch break on the phone with a male friend of mine who’s in a committed relationship; married, with children. The conversation revolves around some chic that wants to be ‘friends’ with him. According to him, she’s clearly stated she’s ready to play the mistress, his out-of-town gig blahdey blahdey blah.
Well, he called me because he needed a sane person to confide in as he couldn’t bare it all to wifey (insert angel face here). When I asked if they’d had sex, he was quick to yell “No o” in his thickest Eastern accent. “I love my wife”. “No. Can’t cheat”. I sighed relief and then delved farther only for him to admit they had smooched, kissed, made-out etc but he hadn’t stuck it in.
Now,that just confused me. A few minutes ago, he said he had had nothing with the lady and declared how he couldn’t cheat on his wife. And then says this, maintaining his innocence. Isn’t that just contradictory?? When does having sexual pleasures with anyone other than your spouse not equal to cheating?? Has cheating been redefined?? Is it now okay to kiss, fondle etc someone else so long as there’s no penetration? I’m about to nail him to the cross, but, I need to be sure he’s actually done something wrong and I’m not overreacting.
Someone please help me. Sincerely, I can’t comprehend this.