"Between Your Girlfriend and I, Which One is Better at SEX?" - Tempting NTR Love Triangle

"You have a girlfriend, but you came inside me." I joined a club when I entered university. On the way home from a drinking party, I felt like someone was following me. I looked back, and I saw a fellow club member I met at the drinking party. When she entered my house, she took off her clothes and pressed against me. I tried to drive her away, but...