Same can be applied to women as well though. But to answer you question, maybe because they aren't really into the whole "committed" part of a common relationship and, for example, see it just as more stable route for getting sex. But then again, just flirting with another person doesn't make that person a side anything and shows of interest is a rather vague statement. I mean someone might think one action is a show of interest and another might not.
The point is, where they draw the line. If you flirt in a joking way but do not start touching the girl, okay...
But if your guy is goint TOO far with other girls you should confront him. Honesty and dedication to each other is everything in a relationship. If he plays games with you, he should admit his mistake and learn from it or lose his girl :-)
I'll post you a friendship request, feel free to accept. I'm from Belgium.
Same reason girls have 'side guys' during relationships. Right now I seem to be the 'side guy' in a relationship and from my observations its because she seems to be bored of her current guy. When it comes down to it is probably for fun, regardless of if its just playful flirting or not.
Men usually have side chicks so that in case their girlfriend or "main chick" breaks up with them, they can just run to their side chicks for whatever they need or want (like sex) until their " main chick" takes them back. They're basically just using the side chick as a back up plan .And some men have side chicks simply because they are greedy and don't know how to be faithful to one woman.
Selfish as it sounds, its sometimes because their other half is cheating on them. Their insecurity level goes down because they don't feel good enough, so they have to find someone else to get the esteem back up..
backup plans: have you ever wonder how guys move on so quickly with a girl (u didn't even knew exist) after things fall apart? He didn't meet her AFTER you guys were over.. that's for sure. I sense this guy was gearing me up to be his side chick/backup plan because he started texting/calling/flirting with me when him & his girlfriend were having problems & on the verge of breaking up ( they eventualy split) I figure he was using me to deal with their problems...so yeah he got booted.
substitute lover: girlfriend is away, girlfriend getting on his nerves, girlfriend is making him feel jealous, girlfriend is making him feel insecure, girlfriend is not spending enough time with him, girlfriend is ignoring him (the guy literally told me this) girlfriend just made him upset, girlfriend tells him they need to take a break... time to hit up the substitute lover. basically he only knows the substitute lover exist when he isn't on good terms with the gf.