Re:
Found Fiance In Bed With Junior SisterMy advice, Keep your sister at arms lenght henceforth or she could do worse than that, not just with your man. I had exactly the same problem with my elder sister, i was in the same state too like you the last time. (that was the 3rd one). She didnt stop there she turned the men, my family and friends against me too. nobody believes my story, she was realy slipppery. Men are gullible, they are easily seduced. The man himself is not good enough for a husband. Keep them both quiet for now. For the man keep him quiet for life. Your sister is your sister though. But she could be more dangerous than you think she is. Next time it could be your livelihood. If she could persuade the man to leave you, she would do it.
You are blood relations, but do not let her into important issues in your life anymore. As for the pregnancy, go for a d and c, it is still early. Move on with your life. You will be glad you did. There are bettr men out there.