What is the ruling on communicating with a married woman whose relationship led to her divorce, and what is the ruling on marrying her after her divorce?

What transpired between you and the woman, in terms of acquaintance and conversation as described, is a manifest abomination and a cause for temptation and corruption. Your declaration of love to her while she is still married is an indirect proposal [to marry] and a heinous sin, as well as an act of corrupting the woman against her husband. This is one of the most detestable sins. Inciting a woman against her husband is among the gravest of sins. It is incumbent upon you to completely sever your relationship with her, to abandon this sin, to regret your actions, and to resolve never to return to it.