Well......apology to me doesn't mean you that is apologizing is wrong and your partner right, it does means that you value ur relationship above ur ego.
Have you 4goten that it is only a strong mind that apologizes when it's wrong and that it takes even a stronger mind to apologize even when it's right? Beliv me, ur guy might b feeling guilty inwardly but he is timid or shy to xpress it, to u, u might see it as being strong-minded but to us that understand, it is fear n timidity. Call him and talk to him, however, don't stop apologizing.