The relationship between a fan and an idol/artiste is just like a business relationship. The artiste’s performance is the product, and we are the consumers. So what we are essentially buying is simply their performances. And this transaction is no different from us going to buy any other product, for example an iPhone. So let’s say I love the iPhone, and I go to extremes to get my hands on the latest model, and buying all the other accessories that come with it. I am spending the money out of my own free will. But I would not care if the owner of Apple gets married or what, as long as they continue producing quality products.
So, it’s the same as us spending money on albums, concerts, merchandise and others stuff of our favorite artiste. Cuz from the start, their job is to perform, and their performance is what they are selling. And we buy it because we like it. So unless the quality of the product ( in this case the performance ) drops, there is no reason why we stop supporting an artiste just because he/she has a (normal) private life that we disapprove.
Side note: I feel that there must always be reasons behind every action a person makes. So why are we judging or jumping to conclusions when we do not know the real reasons behind?