After viewing a lot of articles, I found an English concept that we do use in everyday life. I am not sure for what I found is correct and I hope somebody could validate the concept for me.

I found out that whenever you try to explain the current fact, present tense can always be used. Following is the example I use to elaborate my point.

A) During that trip, I found out who I really am.
B) During that trip, I found out who I really was.

I found out that the sentence A above is a valid sentence because it indicates what you found out about yourself and who you think you really are in life! In other words, sentence A is used when you try to explain to other people who you really are or what kind of people you are in life. Sentence A never expires so present tense can always be used.

However, for sentence B, it is only used for your to explain what you found out in the past for who you were but you no longer are now in life. Sentence B simply describe the things that expired in the past.

From the above concept, I am able to derive the following statement that I hope somebody could check it correctness for me:

(Frank found out who he was 5 years ago.)
Frank: I took a trip to Europe after I got divorced with my first wife. That was the time where I found ut who I really am. I found out that I am not a family man who would spend his weekend with his family and accompany his wife to her shopping spree. I found out that I really love my job and I would spend more than 12 hours a day for my job. In other word, I am a workaholic. I think that is the reason why my first wife left me. However, that is who I am and what God made me to be. I just hope that I could find a woman who could understand me and willing to marry me for being who I am.

Is the above statement I write correct? Is my concept correct?
You have a choice of past or present tense in this kind of situation, that is, when the condition is still true:

She says that the earth is round.
She said that the earth was round. (dependent verb can regress with main verb)
She said that the earth is round. (dependent verb can remain in present tense to reflect present situation)

I admit that I am tired.
I admitted that I was tired. (Ambiguous: I may still be tired, or I may be speaking of a former condition)
I admitted that I am tired. (I spoke before, but I am presently still tired)

So some of your understanding ('Sentence A never expires so present tense can always be used') seems accurate, and some (X 'Sentence B simply describes the things that expired in the past') does not.
Thank you, Mister Micawber, for your patient reply. I am a stubborn man who didn't read through the answer you gave me and repeatedly reasked the same type of question I had asked before. However, I think having a time break for me to calm down and to rethink what I asked helped me a lot in understanding how the English people think in thier own language. Thank you for showing me the new way of thinking in English.