Is it possible and religiously permissible to sincerely and righteously supplicate for the return of a former suitor, from whom one separated due to family problems, especially after he became engaged to another?

It is permissible to supplicate for the return of a young man, even if he is married. However, if he does not wish to marry, one must strive to remove any attachment to him by seeking Allah's help, cutting off the causes leading to attachment, occupying one's time with beneficial things, and frequently supplicating for a righteous husband. For Allah knows what is good, as He says, "And perhaps you dislike a thing and it is good for you; and perhaps you love a thing and it is bad for you. And Allah knows, while you know not."