During Ramadan there was an argument between me and my husband, and I said to him: The limit of Allah is between us, but I did not specify anything in particular. What is the expiation for that? Is it regarded as tahreem (making intimacy haraam) between husband and wife?.
Talaaq and zihaar (kinds of divorce) are the hands of the husband, not the wife. But if the wife declares her husband to be haraam for her, that is an oath (yameen), so if the oath is broken she has to offer expiation for breaking an oath. The oath is broken if he has intercourse with her.
This has been discussed previously in the answer to question no. 110010
Based on that, if what you meant when you said, The limit of Allah is between us, was to make your husband haraam for you, then when the oath was broken you have to offer expiation for breaking an oath, which is to free a slave or to feed ten poor persons or to clothe them. The one who is not able to do any of these has to fast for three days.
But if you did not intend to make your husband haraam for you, then you do not have to do anything.
And Allah knows best.