Sex the night before would not change your results. Even if you contracted HPV from your partner that night, it would not change the cervical cells overnight. I have had two abnormal pap smears and two coploscopies and have tested negative for all STDs, so this does not automatically mean that you have an STD.
Make sure that you read all the instructions for the colposcopy because you are not supposed to douche, wear a tampon, or have sex the day/ night before the procedure. You are also not supposed to do any of those three things in the week following the procedure because they slow down the healing process, can worsen the wound, and can be VERY painful.
Good luck. I hope you have favorable test results.