I find nothing wrong with casual *** (with protection) or paying a professional for ***.
I do, however, have a strict sense of duty and morality...
It goes like this: Marriage is not a joke. You ener into the contract of marriage to signify your love and devotion for your partner and also to signify your desire to start a family.
As such, you are legally, morally, religiously and spiritually bound to the terms of that contract. And if the terms of your marriage... (considering you're a Christian or of a similar religion that endorses monogamy, married legally in a country which requires it, and not a Moslem married under Arabic law or whatever...) require faithfulness, then breaking those terms is no joke. It's a social/legal/spiritual contract, the breaking of which I hold in higher contempt than breaking a simply sales contract or business agreement.
Honestly... in this day and age, where we marry as adults, of our own free will... what reason is there to be unfaithful? If you don't think you can be satisfied with one, then the answer is simple...
don't get married.
If you're getting married for kids and not for love and commitment... well, the law allows illegitimate children the right to take their father's name, and the right to an inheritance already... so
don't get married.
If you don't think you can stick with it for fifty or sixty years, you're not ready for it, really. And if you're in it when you realize this, well... sorry... there's always divorce or annulment... be honest enough to officially end your contract before going against its terms...
But if you're doing that just so you can go out and buy a skanky, smelly piece of STD-infested ass instead of getting it from a lovely woman who's already willing and devoted to you... there's probably something majorly wrong with you...