YES but it takes time. As much as you love a person it takes more time to forget but the feelings of second love is less than their first love. The truth is that he loves a girl to forget his first love and after that he falls in love with that girl. He can love someone else but cannot forgot his first love.
The boy keeps trying to convince himself that he only loves her but when Another Girl comes in his life who takes great care of him, then his life begins to change. All his old thoughts go away and new thoughts are coming for new girl. He starts comparing both girls to each other and the conclusion appears that the second girl is better than his first girlfriend so he attracted to her and fall in love again.
SCIENTIFIC REASON-
Our subconscious mind needs fulfillment. Suppose you thinking about a girl and you want her in your life, and you get her, then your mind fulfilled with that particular thing. when a girl dumps you , you feel as much as you had in the happiness you received. and when our suffering diminishes our mind again need a fulfillment. Not for same girl , maybe different.
Also remember
“IT DOESN’T MATTER WHO HURT YOU, OR BROKE YOU DOWN. WHAT MATTER’S IS WHO MAKE YOU SMILE AGAIN”