Taking a step back and really looking at who they really are, how they really behave, not hiw I imagine them to be or intentions I assume they have.
Either because they turn out to be pretty bland people I have been able to bulid fantasies around or because our issues was actually just their bad behaviour that I was able to imagine excuses for, or because I realise that we are not a good match (we want different things or tend to trigger each other in unhealthy ways) and a relationship between us would be more hurt than it's worth.
Like you seeing her ableism and homophobia instead of just your fantasies around who she is and how your relationship would be.