Submission of wives to their husbands, children to their parents, etc. is often misunderstood by those who have not tasted the grace of God. You didn't say if your friend was a Christian, though it doesn't sound like it. The ways of the Gospel are right-side-up in an upside-down world, so they are going to look/sound odd and even offensive.
Sadly, even many Christians have misunderstood what godly submission is, and have preached something which God did not intend. If one starts with the goodness and love of God shown to us in Christ Jesus, and works through God's designs for creation, salvation, relationships, and marriage, submission sounds a lot better. Without the context, it can sound like subservience or subjugation, which it isn't. Also, it is often taken out of context. "Submit to one another, out of reverence for Christ" is not "wife submit to husband regardless of his behaviour". It is balanced; both husband and wife submit to the Lord first.
Christians don't all agree on the interpretation and application of marital submission; some believe that it should be mutual, some believe that it should be wife-to-husband primarily (that's a simplification!). I would encourage you to do your own study on this subject. Know what you believe, and hold firmly to it. No need to apologize to your friend, but perhaps it is an opportunity to share the basic truths of the Gospel. To give her/him the broader context, you know.