Seriously man, a quick kiss and then a regret is one thing that you could debate about.
But a minute-long french kiss is something that she had plenty of time to think about, and not something that is easily forgiven. Just imagining that she let some other guy put his tongue down her throat for a freakin makeout session isn't exactly "innocent" testing... what exactly was she hoping to "find out" from one kiss with this other guy? Well since he kisses this way I can definately tell everything about who he is as a person... blah blah blah. Most BS story I've ever heard.
EDIT:
Honestly I think her story is a way of dodging blame for her actions. Tell her you've thought about it and show her it was serious and break it off with her. If she honestly had some doubts about the relationship she could have some freakin courtesy to talk to you about it and deal with you in a way that shows she cares about you. Nah, she's lieing to you, she saw some guy, was attracted to him and wanted him, she didn't give a flip about you or your feelings... she was too busy enjoying the moment to care. THATS the truth about this situation, not her glossed-over "I did it for us" guilt-dodging BS.
But a minute-long french kiss is something that she had plenty of time to think about, and not something that is easily forgiven. Just imagining that she let some other guy put his tongue down her throat for a freakin makeout session isn't exactly "innocent" testing... what exactly was she hoping to "find out" from one kiss with this other guy? Well since he kisses this way I can definately tell everything about who he is as a person... blah blah blah. Most BS story I've ever heard.
EDIT:
Honestly I think her story is a way of dodging blame for her actions. Tell her you've thought about it and show her it was serious and break it off with her. If she honestly had some doubts about the relationship she could have some freakin courtesy to talk to you about it and deal with you in a way that shows she cares about you. Nah, she's lieing to you, she saw some guy, was attracted to him and wanted him, she didn't give a flip about you or your feelings... she was too busy enjoying the moment to care. THATS the truth about this situation, not her glossed-over "I did it for us" guilt-dodging BS.