Having a disagreement with someone is not a sin. How you handle that disagreement can be.
- If you let your anger get the best of you, if you were uncharitable with her, insulted her, or got abusive, then yes, you've sinned.
- If you let your pride about being right motivate the argument, then yes that's sin.
- Anytime we let the little things in life, that really don't mean much from an eternal perspective, get in the way of charity and love, then we sin.
But guess what, we're human. Couples argue. Friends argue. Family members argue. We get angry; we say things we shouldn't.
It's good that you recognize your shortcoming and apologized. Marriage is a sacrament by which the spouses sanctify each other.
Sometimes, that process involves being like sandpaper towards each other, filing off the rough edges. So arguments are opportunities to grow and to make up and forgive one another. For this reason, at your next Confession, you can mention it, especially if you got abusive and hurt her feelings but go the extra mile and make her feel loved.
She's a lot more important than a coupon and a furnace!! So make her feel that way but don't kick yourself about this.
Even if you did sin, odds are it's not a mortal sin. You probably reacted without sufficient time to reflect on your words and action. So you've asked her to forgive you; so, again, at your next Confession, ask God to forgive you. I recommend monthly Confession anyway irrespective of any mortal sins because it gives us the opportunity to reflect and examine our conscience.
Sometimes, if we go only when we've committed a mortal sin, which weighs so heavy on us, we forget to look at the other less obvious sins we all commit on a daily basis.
Obviously, your heart is in the right place or you wouldn't have asked us this question so don't beat yourself up. Remember God is working on you.
Learn to yield to His Work in your life and let Him do it in you.