All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
As long as your husband said that you going out on that same day was a condition for the divorce, then the divorce did not take place by you leaving the house after that day without his permission. Ibn Qudaamah said: “If a certain time or circumstance related to that time is made as a condition for divorce, then divorce does not take place unless the circumstance and the time occur.”
However, you are sinful for leaving without his permission; it is not permissible for a wife to leave her husband's home without his permission. Shaykhul-Islam Ibn Taymiyyah said: “A wife is not to leave her husband’s home without his permission, whether her father or her mother or anyone else tells her to do so, according to the consensus of the scholars.”
Therefore, you should seek forgiveness from Allaah for leaving your husband's home without his permission and ask your husband to forgive you for having done so. As regards divorce, it did not take place because he did not make leaving in general a condition for it, but specified a particular day.
Regarding the issue of the husband having sexual intercourse with his wife when they do not know that they have become forbidden for each other, they are excused if laws of that nature are unknown to people like them. But one is not excused on grounds of ignorance if one commits what is forbidden while such a forbidden matter is well-known to everyone. As-Suyooti said: “Anyone who does not know that something which is common to the majority of people is forbidden, it is not accepted, unless he has only recently converted to Islam or he grew up in a remote desert where such things are not known to them, such as the prohibition of Zina (fornication); killing; stealing; wine; speaking in the Prayer; eating while fasting; killing by the testimony (of two witnesses), if they retracted and said, we did so deliberately but did not know he would be killed by our testimony; intercourse with a female slave who is usurped or given as a security without the permission of the owner, but if it is with his permission, it is accepted unconditionally, because all that is unknown to common people.” [End of quote]
However, this rule is not related to what you asked about because your marriage is valid and ongoing and the divorce did not take place by you leaving because your husband made you leaving on that same day a condition for the divorce and not leaving without his permission at all times.
Allaah Knows best.