[EtherC]

Two different leagues we are talking about here: experienced professionals vs everyday people.
If your gf/wife is intimately familiar with various karmasutra positions, you’d need to consider how she got that good. Makes her more risky in terms of fidelity don’t you think? Unless you are some godly porn stud or you can lick your eyebrows, then you are on the level playing field.
Takes time , luck & effort to be able to find your compatible match. And compatibility does not mean perfection. Perfection is an ideal and even perfection over a long period is gonna end up in boredom.
You can only be happy if you understand gratitude.