I was in a deep relationship with a girl who was infact my first love. She was loving ,talented ,beautiful and a successful Lady.But things did not work out between us.Now that she is already married with kids, i am trying to move on. I have been dating a girl and my heart and mind forces me to compare between them like how loving ,generous and talented she was. I cant stop thinking about all the pleasant things about her but this makes me feel guilty towards my new relationship. Is this all natural to think about your past love? Thoughts to have that it could have much more better to have her in my life?How do i stop thinking about her? Please Help me with my mental fight.Thanks in advance.

PS only honest suggestions please.