Head this story recently that makes you think.
 
Came across a lovely girl who'd who told me about a relationship that had started with housemate of hers.  She'd adored him and did everything he asked, he'd made her feel good and continually led her on.  There'd been lots of laughter and she'd been really happy.  She much later discovered that he'd been sleeping with other female housemate (who knew about my friend) and had full on relationship with her at same time.  Talk about scheming.
 
Girl I met had known nothing at the time, although been suspicious and was devasted when she found out - felt completely used and betrayed.  All that deceit - what a nasty discovery to make.  Told her she's better off without him (I'd post his photo and details around but she's not interested).  Definitely not nice. 

Just makes you wonder about some people...