Mangas like this are what makes me believe that the score on Mangadex are just randomised.
That chick is like... the worst.
She drinks, smokes, gambles, sleeps around (not confirmed but clearly does) and in general does everything that she thinks is 'wrong' because she finds it exciting.
She is pretty much the worst choice for a gilfriend ever who will gamble away everything till she is in huge debt, constantly show up drunk halfway through the night and cheat on your before you are even a few months together.