She gave up oddly easily given how her character was portrayed last chapter, bit I'm reading it as she came to the realization she actually likes both of them (or at least Renge) and couldn't bring herself to continue.
Nah. Not when you realized that the guy never actually went along with accepting her advances, even after she showed her breasts. Everyone else that we saw in her flashback, regardless of their words, accepted her. Even the Father/Husband did, since we can see the guy's hands on her waist. MC on the otherhand? Nope, he kept his hands to himself, he never accepted her advances or touched her sexually. Combined that with his tears, his entire body language practically screamed "Rejection" to her.
And if it's like what some of the other posters said, if she's about consent (even if it's dubious), then she won't go any further. However, I don't expect this to be the end. If anything, I wouldn't be surprised if she tried again, however just like here, if he doesn't accept, then she'll back off. If she's serious about ruining the MC and the FL relationship, then she'll keep trying for as long as she could, until the MC breaks and accepts. The biggest advantage that she has here is that "she's drunk", so she can play it off as not remembering, and she knows that MC is too nice to tell anyone about this.