Does divorce occur through an implicit statement (kinayah) that was not accompanied by an explicit utterance, or through an implicit statement uttered by the wife that was not accompanied by the husband's intention of divorce? Or does contemplating the matter not lead to certainty, and what is the ruling on divorce by implicit statement if the question arises 20 years after the incident?

Your statement: "If I speak to this person, I will not complete the marriage process," does not necessitate a divorce. It is neither an explicit divorce pronouncement nor an indirect one. Rather, it is merely a self-talk or a threat. A threat of divorce does not entail anything, especially given the severe waswasa (obsessive whispering) regarding divorce matters. Therefore, no divorce is incumbent upon you because of what occurred. It is advisable to disregard these waswasa and seek refuge in Allah from them.