All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
First of all you have to supplicate Allaah, the Glorified and the Exalted, to keep your husband away from all prohibitions, put your love in his heart and make you dearer to him. Allaah, the Glorified and the Exalted, alone can turn the hearts of people and He alone responds to every one who supplicates Him.
You are advised to get close to Allaah, the Glorified and the Exalted, by following His commands and avoiding His prohibitions. Ask Him during the times when supplications are most probably responded to. See our Fatwa: 88296.
Try to know the reason he is interested in another lady; maybe you are not behaving with him as he likes, or maybe you are not adorning yourself enough or too busy to do so, while generally men are fond of beauty. So, adorn yourself, be well-dressed when he is at home, spend much time with him, and respect his likes and dislikes.
On the other hand remind your husband, wisely and softly, of his obligations and exhort him to fear Allaah, the Glorified and the Exalted. Tell him that Allaah, the Glorified and the Exalted, commands men and women to lower their gaze and not look at the opposite sex. Talk to any religious and influential person or someone who can convince him and make him to give up such sins. To know the ruling on chatting between sexes via internet see our Fatwa: 84932.
Turn towards Allaah, the Glorified and the Exalted, supplicating for your husband and try your best to settle these matters with your husband. May Allaah, the Glorified and the Exalted, grant you a happy life.
Allaah Knows best.