Your friend is correct. It is unlikely to stop gambling when you win a big prize. Even if you understands that stopping is the best option, you may return again someday. It must be a temporary stop only. When you have spent all the prize, I'm sure you will return to gambling again. If you really want to stop, you need a stronger reason. 
Anyway, why you choose an option of gambling? Don't you think to trade crypto coins? This is also a fast way to earn money. It is more secure than gambling if you choose spot trading. However, it requires a lot of money if you want to get huge profits. But the safe thing is that you won't be addicted to gambling if you choose trading.
Anyway, why you choose an option of gambling? Don't you think to trade crypto coins? This is also a fast way to earn money. It is more secure than gambling if you choose spot trading. However, it requires a lot of money if you want to get huge profits. But the safe thing is that you won't be addicted to gambling if you choose trading.
Big wins or big lose would surely get you more attracted towards gambling. A person who might lose everything might have a chance to come back to sense and with regrets of what he've done stop gambling but a person who is on the winning side would not be able to stay away from gambling.
Personally, I gamble as a way to entertain myself and if I have other things to remain content and when I lack spare time, I don't gamble. My personal gambling time and amount has decreased significantly from a year ago as now I'm placed in an office with heavier work load than it was in my last office. Similarly I've seen many of my friends nearly stopped gambling after they got married.
On the other hand, you have a pretty good approach to gambling which happens because you have a wise mind in distinguishing between which should be prioritized between gambling or your main job.
And that's how it should be, in the sense that if you don't have free time or money to bet, then don't gamble, because after all there is no coercion from any party to you to continue to force yourself to gamble all the time, and that way the approach will keep you safe and avoid various possibilities of depression in gambling as experienced by gamblers who always act excessively.