No CP = no couple

The protagonist either

1- doesn't have any romantic relationships at all and never thinks about having one.

2- Has romantic entanglement with others, but for reasons such as:

a) being rational, perfectionism or a natural scum they can let go of the relationship and move on, either into a new relationship (which won't be their last) or choose to be a lone wolf as being in a relationship doesn't bring them satisfaction [Aka in this situation the problem is from protagonists themselves] 

 b) Their love interest(s) have problems either scum or villain, meaning there is no love interest suitable for a serious relationship. In this stories, protagonists clearly know their wants and needs, and the importance and factors of a healthy relationship, they are mature and sensible, and don't mind having a relationship but won't force it