MrOlai:
1. Legality
Marriage Sex is sanctioned by God while Fornication/Adultery Sex is sanctioned by devil.


2. Reward
In marriage sex, God would reward husband and wife after every sex they have together. In fornication/adultery sex, God reserves severe punishment for the doers except they are forgiven by God.


3. Sweetness
Marriage sex sweet die! Chai! It is sweet at the beginning and it is also sweet at the end. However, in case of fornication/adultery sex, it probably might be sweet at the beginning. It would surely end with guilt, sorrow, etc.


4. Results/Products
Marriage sex yields good products, ceteri paribus, viz-a-viz happy home, bond of love between husband and wife, good children, good focus, strong ties of kinship, long life, prosperity, etc. However, fornication/adultery sex yields evil products viz-a-viz broken home, abortion, cancer, guilt, shame, bastard children, death, losing virginity to somebody who is not one's spouse, loss of womb due to abortion, etc.


5. Freshness of Face/Personality
Marriage sex keeps the faces/personalities of the husband and the wife fresh. With time, both of them would look alike to people outside as if they are siblings due to the constant exchange of 'paps' between them. However, fornication/adultery sex makes the doers ugly even with make-ups! Reasons for this include Telegony involving different 'paps' for women, guilt, shame, divine punishment, psychological trauma, etc.

Vikkie14:
Your points are surgical.
If you agreed with OP, hit LIKE.