Girls, how you will protect your relation if there's another girl?

You are in a relation with a guy you truly love and there's a pretty girl (you are pretty too ^_^) you fear getting closer to your love and when you try to convince her to keep away she gives you these two options and says you'll never see her again after one of these happen. What you do?
Having you in her bed one night
Threesome with you and your guy
Select gender and age to cast your vote:
Girls, how you will protect your relation if there's another girl?
Post Opinion