Dr. Ragab Abu Maleeh Muhammad, an Islamic researcher, says:
It is not lawful for a married woman to desire somebody other than her husband whether in this world or in the Hereafter. It is stipulated in Islam that both spouses find satisfaction in one another, that is, that neither of them is to look lustfully at a person other than his or her spouse. If a married woman feels that she is about to fall in love with a man other than her husband, or that an old love story of hers is waking in her heart, she must immediately awaken herself to the fear of Allah and do her best so that she can block all the ways leading to that thorny path.
We should know that there are steps of marital breach; each step taken leads to a further (and riskier) one. The first step starts when a woman desires a man other than her husband and seeks to be where he is and talk with him, which leads, at the end, to the ruin of her marital life.