Is a woman's feeling of love towards a man other than her husband considered a sin, even though it is merely an internal feeling and does not go beyond that?

The husband's neglect and disregard of his wife are impermissible. She should be frank with him and discuss the reasons for this. A wife's feeling of love towards a man other than her husband is impermissible. She must repent, seek forgiveness, and sever all ties that bind her to him, if she was the cause of them. However, if the love is not acquired [i.e., not intentionally cultivated], there is no sin upon her as long as it remains within the realm of inner thoughts. The wife incurs sin if she intentionally seeks pleasure and happiness upon seeing this man and hearing his voice; she must turn away and distance herself from him.