Is this a cheating?

(Situation) A boy and a girl had a relation for 6+ years. Both worked upon many things be it themselves or career and did enjoy happy moments and each other company.

Like any other relation, there were disagreements, fightings and arguments. And after months of repeating cycle of disagreements and arguments, one fine day a boy is being questioned about his love and was also asked to mention the happy moments both have shared till now? A boy was shattered completely and decided to take a break from this relationship to think whether he should continue or add a full stop to it. He conveyed the same to the girl.

To which, Girl took break as a break-up. And states herself vulnerable and starts to fall for the other person who was her colleague.

Earlier she did state the colleague as a friend and now says she couldn’t hold up her feelings for him (the colleague).

Didn’t she cheat on His 6+years boyfriend?