If you want to be a better person, there is no better place to work on this than in your relationship. Every day, you can work on how you talk to and treat your spouse. Be vigilant of the words that you express so they are respectful. Be thoughtful of your behaviors so you are considerate and kind. If you are tired, moody, or irritable, be cautious not to take it out on your partner. If your partner mistreats you, be disciplined not to respond in kind.
These are simple suggestions but challenging to implement in the moment. Please practice. You make thousands of little choices to determine the quality of your relationship.