Does a wife's thoughts and dreams of her ex-lover count as betrayal to her husband, and what is the way to get rid of these thoughts and dreams?

The best way to rid oneself of attachment to a man is to turn to Allah through supplication (du'a), and to engage in reciting, pondering, and listening to the Holy Qur'an, for it is a healing for hearts. Also, frequently remember Allah to fortify the heart against the whispers of Satan. One must cut off everything that reminds her of this man. When he comes to mind, one should seek Allah's forgiveness and refuge in Him. When the heart is filled with the love and glorification of Allah, it will not become attached to anyone else. If his memory overwhelms one and she strives to dismiss it without engaging in anything forbidden, she is not punished for it, nor is it considered disloyalty to her husband. Contacting him by phone or similar means is a reprehensible act and a betrayal.