Emotions have a way of complicating an issue making right seem wrong and wrong seem right. I ask you, you loved your husband before you married him, and this other you love, and if opportunity presents itself, you will marry him. What leads you to believe that there is any difference between your husband and this man? Up until now, there is no evidence, that you will be more predisposed to having an intimate relationship with this man if he should divorce and thus able to marry you. Although you do not say about your marriage, it would seem that everything is fine with the exception of the matter of intimacy. You made it clear that the problem is with you, so why did you not seek counsel for yourself as opposed to being between you and your ex-husband. You did not show that your husband was unhappy, and in fact he was reluctant to divorce you, and yet you are frightened of living a life that is wrong?

"A man divorced his wife and she married another man who proved to be impotent and divorced her. She could not get her satisfaction from him, and after a while he divorced her. Then she came to the Prophet and said, "O Allah's Apostle! My first husband divorced me and then I married another man who entered upon me to consummate his marriage but he proved to be impotent and did not approach me except once during which he benefited nothing from me. Can I remarry my first husband in this case?" Prophet Muhammad said, "It is unlawful to marry your first husband till the other husband consummates his marriage with you" (Bukhari 7: 63 #190)

The virtue in this is the act that will help determine whether you and your husband are unsuitable. Islam always looks at both sides of the story. in the following ahadith mercy as demonstrated:

"The wife of Thabit bin Qais bin Shammas came to the Prophet and said, "O Allah's Apostle! I do not blame Thabit for any defects in his character or his religion, but I am afraid that I (being a Muslim) may become unthankful for Allah's Blessings." On that, Allah's Apostle said (to her), 'Will you return his garden to him?" She said, "Yes." So she returned his garden to him and the Prophet told him to divorce her" (Bukhari 7: 63 #199).

In other words, your mahr, (dower) returns to your husband. In your case, the problem was not coming from your husband, but from you, and marrying again will not necessarily solve the problem, unless the source of the problem was that you had no physical attraction towards your husband.  

The wrongness my dear is that you did not make the most of your marriage, and that the one that you love asked you to leave your husband, and then years later, considers leaving his marriage in order to marry you.

Narrated AbuHurayrah: Prophet Muhammad (peace be upon him) said: Anyone who incites a woman against her husband… is not one of us (Abu Dawud  12 #2170).

Neither of you have shown commitment towards your marriage. The only saving grace in the situation as it stands now, is that the man you love has a son, a son who he has some level of paternal attachment to. I ask you, if you were in his wifes shoes, would you want your husband, your son's father to stay, or to leave? The only real condition for having a second wife, is if the first wife cannot have a child. I think you have not considered being a second wife, but why should she consider being a divorcee to satisfy your need? Yes, they are unhappy, but is the wife unhappy because your are in the picture? Is it not the case that her husband did not think of divorcing her until he knew that you were and are divorced? What was their marriage really like before you divorced?

My dear sister, reality can seem so harsh, but this harshness is sometimes what is needed to wake us up. To part a father and a husband from his son and wife, is no greater sin than that which could happen to you. Be a sister in Islam, and try to review what was good about your marriage and what is within you that prevented you from being satisfied with that marriage. A man of deen was a man you loved, what more could a woman ask for? Intimacy does not begin in the physical but in the way you communicate, understand, feel for one another and share everyday things and issues with each another.

- Sabnum Dharamsi  -

"Narrated Al-Hasan: The sister of Ma'qil bin Yasar was married to a man and then that man divorced her and remained away from her till her period of the 'Iddah expired. Then he demanded for her hand in marriage, but Ma'qil got angry out of pride and haughtiness and said, "He kept away from her when he could still retain her, and now he demands her hand again?" So Ma'qil disagreed to remarry her to him. Then Allah revealed: 'When you have divorced women and they have fulfilled the term of their prescribed period, do not prevent them from marrying their (former) husbands.' (2.232) So the Prophet sent for Ma'qil and recited to him (Allah's order) and consequently Ma'qil gave up his pride and haughtiness and yielded to Allah's order" (Bukhari 7: 63 #248).

For your further guidance, please try the following links:

Valid Reasons for Divorce
•   Divorce Should Be the Final Resort

•   Effect of Divorce on Marital Home and Child’s Custody