I don't think he'd dump Layla for Nikki after taking Layla's virginity. I think it'd be an internal monologue, and because he realises how shitty that would be you wouldn't get a choice and he'd dump Nikki in that scenario. If dating Nikki and another girl then you'd get the choice on who to dump. So it's dumping Nikki if you take Layla's virginity that is the forced break-up scene in that scenario.
You made the choice to take Layla's virginity after giving that promise to Nikki, it would be easy to have MC's inner monologue declare that he had broken the promise to Nikki by sleeping with Layla so the right thing to do would be to dump Nikki.
If you didn't want the Nikki relationship to end then you shouldn't have taken a relationship with another girl further after promising her that you'd be finishing any relationship with other girls.
I mean, the MC also takes Cara's V-card and promise the same thing as to Nikki and the MC can break up after taking her V-card or cheat on her with the blond at the bar (Julia ?), i see no reason why Layla should be any different.
Well, after making that promise to either Nikki or Cara at the airport my MC was banging Gabi, going on a date with his gf Alexis banging her too, kissing Erynn, making out with Val and then making out with Iris at the club...ah, also trying his luck with Melissa.
I mean, why force an break up with Nikki/Cara at this point just because of that promisse ?
And Layla is special why, did he suddenly grow a conscience because she was virgin ?
As for sinner dialogue, like the one with Gabi when your on Alexis path ? Which amounted to, ''fuck what i'm doing! well i still like Alexis, so why did i cheat on her ? Because it's fucking Gabi!''
