Did my girlfriend cheat or not?

My girlfriend and i got in a huge fight over the phone and we disucussed maybe breaking but we didnt...she still took it hard and said she took it like a break up emotionally because she thought i found someone else.she is completly in love with me.one of her friends came up and comforted her while she told him how much she loves me in tears and how she thought i was the one. he talked about how he lost his first love trying to relate to her. he ended up lifting her chin kissing her for 3 seconds she said she puckered by reaction (unknowingly accepting it) because she wasnt thinking about it at all, and tried to put his tongue in her mouth. she said that woke her up cuz his tongue and the taste of cigs and she didnt know what was happening really because her mind was elsewhere and she was thinking about me the whole time and didnt think the dude would kiss her while she was crying so hard and thinking about moments we had in the past. She said she was just love sick about me and thinking about me and wishing i was there and asking herself why i hurt her so bad and thqat she didnt deserve that and deserved better. and she was crying really bad and was completly vulnerable..she didnt think of the kiss at all. her friends and brother even said she was crying harder then theyve ever seen even though she said the dude calmed her down to a 7 outta 10 crying instead of a 10/10(scales how siverly she was crying). she is really a nice girl and isnt the type to cheat...ever. But is this plausible? can you not know what your actually doing when ind deep thought? Is my girlfriend a cheater? Opinions?