It depends on the story and character's commitments.
I have a novel where the man's only goal is to become a good ruler and he will do whatever it takes to get there. He would sacrifice love to become a fair king. So, that novel is a solid level 0.
I have another where the story revolves around a prophecy about a deadly love. The main characters are immortals who understand each other's dark past and together, they struggle to create the life they want. Their relationship almost seems too good to be real and they did fall in love very quickly. This love will be challenged time and time again, but the bond will only get stronger. It's an 'us against the world' type of love. So, that novel is level 4?
The novel I have on Tapas is about two men. Their relationship is a bit odd. One man falls hard while the other one only wants to fulfill the request of his gods. At the moment, the book is at level 1. It may go up to 3.5 (has both elements of 3 and 4).
All this, but fluffy romance is a nono. I make my characters see that love can make or break a person and I always hope the amount of issues are not too much.