Question about cheating – both in the short-term and over a long time?

I hooked up with this girl recently, only for a few weeks – I didn’t sleep with her. Then she mentioned she had a bf for 2 years. (I stopped talking to her). My friend said she was probably having trouble in her r'ship and hooked up to get attention or distraction. That would make sense, if we had just met when that was going on..... Thing is, we met last May, and she asked me to ask her out repeatedly since then! So it basically tells me that for like 6 months she was dating this guy, and open to dating with possible ‘replacement’ boyfriends. So does that mean she’s mean having problems all that time – or is she *constantly* looking for a new branch to swing to, and is dating this guy for some void-filling purpose? What I’m saying is, isn’t there a difference between being vulnerable when times are bad, or just downright unfaithful and completely guiltless about it at **any time?(which appears to be what she was doing) I’m not pursuing this girl – I know shes a****!!! Please no answers telling me to stay away from her and I deserve better and all that..... I know that! Just a lingering thought I have about her character as I move away from this.....