A Haram Love Between a married woman and man?

How does a muslim lady/wife/young mother stop herself from falling in haram love with her childhood friend who is also a friend of her husband.shes married,hes married and although they both watch their adaab because they arent mahram and they are never alone together...he always helps her in her time of need, supports her ideas,looks after her,gives her good advice and makes her happy just by seeing his face.he feels this way about her as well,but they know that falling in love would be haram.she loves her husband and he loves his wife,but something is making her crazy about him...is it naafs or lust or innocent love and how to stop it before it gets worse? btw her looks are bewitching but he has seen her his whole life so that probably doesnt even matter to him.what can she do about that? help!