The Nasty Divorce (of a co-worker)

Here is what I don't understand: how doesn't someone think this is an affair when they slept with someone else besides their spouse?

I'm talking a soon-to-be ex-wife of a colleague. She was caught sleeping with a guy who literally lives a mile away from her husband's and her home. She had the guy sleep over along with their 2-year-old daughter while her husband was out of town. She slept with him, went out with him, slept in his house and list goes on. Yet, she (until right now, they are in the process of getting a divorce) doesn't think she has been having an affair. She calls it, "hanging out."

This sounds extremely pathetic. My colleague asks me today why she doesn't think she has been having an affair all along. Why does still deny it and acts as if it's okay to "hang out." Gosh...I don't think she doesn't know. I just think it's easier to keep denying it instead of admitting she is a slut. Well, see, I think, since she's been denying it now it doesn't only make her a slut, but a retarded lying slut all together. Thinking about this whole divorce thing he has been through, as much as I feel really bad for him, I also think he'd better off without her anyway. At the end of the day, the poor colleague of mine ends up with some attorney fees, court fees, headache custody, child support and on, on and on. Does Thailand's divorce case this complicated? Or is it just here?