Simply because he smiles, talks, or even have sex with you does not mean a married man is in love with you.
They often are in a casual sexual and destructive relationships with you than love.
He Tries so Hard to Win Your Heart Not Your Vagina
A married man is in love with you if he shows complete disinterest in having sex with you before he entirely wins your heart and trust.
He Talks About Leaving His Wife
A married man who is seriously in love with you should and must have uncomfortable conversation of what he plans to do with his current relationship.
If he really loves you, then he can not have both of you or else he is making one of you stupid.
He is a less excuses and more action type of person
A married man whom you have plans with and executes them accordingly is really in love with you.
https://leavehiswife.com/signs-a-married-man-is-falling-in-love-with-you/