My (30M) GF(26F) slept with her boss to get a promotion but now regrets it

We're in a 1 year relationship and we work in the same industry, different companies. She said at the start of our relationship while I was out of town, she had a company outing. Her then boss at the time invited folks over to his place. She ended up being the last one there and ended up making out with her boss. She said they cuddled topless and talked on the couch for a while but then went home later that night with nothing else escalating. Mind you, her boss was never aware that she was in a relationship.

I asked her why she would do such a thing and her justification was that she didn't mean to cheat or see him romantically, but felt that if she didn't please him somehow, she might not progress in the company or get promotions. The next morning she said she regretted justifying herself in that way and that she was only trying to be strategic in the moment.

I told her I needed some time to process all of this but she's been texting me every day saying how much she loves me and that she regrets her actions and wants us to stay together forever.

I get that she needs support from me after this story but also it's time to end the relationship asap is it not?

tldr GF slept with her boss without telling me, but regrets it, and wants to stay together with me