Many of us believe that a strong physical or chemical attraction between people is what determines a good long-term match. We call that love, not understanding that this physical attraction is only one part of what makes a healthy relationship work. And in the long run, it may not be the most important part. There are a lot of qualities we must discover in a person before we decide that we like someone. It takes time to discover these things.
First impressions can be very wrong.
The problem is, strong physical chemistry between two people can blind them to everything else. It is hard to see reality when all you feel is passion. So, we ignore his lies, or her drug use. Don't mind that she is controlling. Refuse to admit that you can't trust him.