Asalam U Alaikum,
الجواب وبالله التوفيق
As per the situation described in your question, the three divorces had already taken effect upon you, when your husband had stated “I divorce her (my wife)” three years back. You are not considered his wife since that point in time. The whole time you lived together after that is considered time spent without Nikah. Any marital relations established during that time are considered haram. You should immediately separate from him, repent and perform astaghfar. When your husband later stated “my wife is divorced upon me” no divorce took effect because you were not in his Nikah since three years. There was no meaning of issuing a divorce anymore. However, it is correct and a fact that you are divorced.
قال تعالی: فان طلقھا فلا تحل لہ من بعد حتی تنکح زوجا غیرہ (القرآن، سورہ بقرہ)
(ان کان الطلاق ثلاثا فی الحرۃ وفی الامۃ ثنتین لم تحل لہ حتی تنکح زوجاً غیرہ نکاحاً صحیحا ویدخل بھا ثم طلقھا او یموت عنھا (کذا فی الھدایہ
واللہ اعلم بالصواب