Kindly tell the right way to check Mangal Dosha in a chart and what is the real impact of Mangal / Kuja Dosha on married life and what is the role of Saturn in connection to Mangal / Kuja Dosha

In my humble opinion destiny is the situation that comes to us, which are beyond our control. But our response to those situations is our choice/ freewill. For example: We didn’t choose our father ( 9th House).We were destined; that was our destiny; we were born. We didn’t choose our appearance/ looks (1st House). We didn‘t choose our children (5th House). So situations are destiny. We didn’t choose them, they came to us. Another Example: If someone comes and insult you, you didn’t choose it, it came to you. This situation is destined. But your response to those situations is your choice/ freewill. What you choose is your choice/ freewill and once you choose it, that will decide your future destiny. That’s why it is told that “Man is the maker of his own destiny”.