Saying that gambling is a choice sounds like a BS excuse to me. Doing drugs is also "a choice". Becoming an alcoholic is "a choice" as well.
Ruining your life is a choice. Sometimes the people lose control over their behavior and their choice suddenly becomes an addiction.
Being addicted is not a choice, it's an illness that has to be cured. The life story you are describing seems like a scam to me.
Letting someone else manipulate and scam you is your choice, but that doesn't mean that it's your fault only. The scammer is also guilty of manipulating and scamming innocent people.