Hi kay!
I, too, have wasted my time in a relationship and I always seemed to have ignored my intuition.
I always saw it and thought that there was something fishy going on but I wasn't able to muster enough courage to dismiss what was happening. And then it got worse but it was mostly because our type of relationship was a long distance one so I was literally blind.
I reached a point when I couldn't hold it any longer so I broke the relationship and I must say that it was one of the best decisions that I ever made.
About intuition: You're right when you described its basis as that coming from previous experiences which involved extreme feelings and emotions. To add to that, our intuitive decisions are also based from long term exposure to some knowledge or practice. I think I read about it on the book "Thinking fast.. and slow" by daniel kahneman(?). Example: Performing math calculations intuitively (I'm not sure if intuition is exactly the term btw), is a result of long term practicing of mental calculations.
At the context of making decisions in life, the reason why it's oftentimes hard to make one is because of our possibly contrasting/conflicting experiences or knowledge. An example is choosing self employment and traditional work. I think we are all affixed to having jobs 'cos that's how it used to work before but then crypto came to our minds and as we learned more about it, we slowly drift apart from old works or way of life. And it's just one of the best decisions to make - to read more about cryptos cos it's the future :)
Oh god, sorry for the long reply ^_^V