lol…that’s precisely your problem, pal.
First, Human Laws are not the final arbiters of what is actually right and wrong because there can be unjust laws.
Second, if you agree to this principle, then notice all the repugnant consequences you have on your hands:
(1) If two parties consent to doing X, then X is morally permissible
(2) Koko and you consent to have sexual relations with one another.
(3) Therefore, yours and Koko’s sexual relations are morally permissible.
(1) If two parties consent to doing X, then X is morally permissible.
(4) Bob and his sister mutually consent to sleep with one another
(5) Therefore, Bob and his sister’s sleeping with one another is morally permissible.
(1) If two parties consent to doing X, then X is morally permissible.
(6) Jane and Bill mutually consent to abort their baby because of financial burdens.
(7) Therefore, Jane and Bill’s aborting their baby is morally permissible.
(1) If two parties consent to doing X, then X is morally permissible.
(8) Bob and John mutually consent to rob a bank together.
(9) Therefore, Bob and John’s robbing a bank is morally permissible.
Should I go on? Or are you finally willing to admit to everyone that you don’t have a case whatsoever?