I (24m at the time) slept with my girlfriends sister (18f at the time)

This happened 10 or 11 years ago. I we were at her 18th birthday party (small family gathering) and she mentioned that she was not doing well in math. My girlfriend mentioned thay I was good at math and that I could tutor her after-school a few times a week.

So for a month we studied a couple times a week and got to know each other and found out we had a lot in common. At the end of our month or studying she had a test and did really well (think 50 student got a 70ish score) and she was really happy. When we got together for her next study session she was really excited and showed me her score. We hugged each other and she kissed me. I kissed her back but then we stopped and realized what we did and said we can’t do this and after a few awkward minutes went back to studying.

I (24m at the time) slept with my girlfriends sister (18f at the time) [MF]

This happened 10 or 11 years ago. I we were at her 18th birthday party (small family gathering) and she mentioned that she was not doing well in math. My girlfriend mentioned thay I was good at math and that I could tutor her after-school a few times a week.

So for a month we studied a couple times a week and got to know each other and found out we had a lot in common. At the end of our month or studying she had a test and did really well (think 50 student got a 70ish score) and she was really happy. When we got together for her next study session she was really excited and showed me her score. We hugged each other and she kissed me. I kissed her back but then we stopped and realized what we did and said we can’t do this and after a few awkward minutes went back to studying.