Gee, I love your typical "liberal Logic Analogy" --- btw I never took a Pro or Con stance to Incest I just asked a question --- and to CORRECT your assumptions, based on your omnipotence, back in the day " " and "murder" were NOT considered to be in the same category as " "...
In many cultures was considered normal and actually required for their Ruling Classes -- example, King Kamehameha of Hawaii was REQUIRED to marry his own sister :-)
But thank you for setting all of us dummies straight on what is right and what is wrong, what is correct and what isn't correct and what is the truth and what isn't... according to the Gospel of Sprite :-)
A very horny, classy, but nasty, sex maniac that is very, very open minded :-)
Obviously the two of you should talk about it (preferably when you aren't sexually turned on) and logically decide what you are BOTH comfortable with doing. Unless you both agree it wouldn't be a good idea to do anything more...