Send a text message to my husband to apologize, but he won't reply. What does this mean?

Not replying means that you still don't want to open your heart to you, or you are used to your way, and you don't believe that you will correct your mistakes and your relationship will get better. In fact, there is no need to apologize, and when you choose to apologize, you should also explain to yourself whether you are really wrong, or whether you are really aware of your own problems and can actively improve them, instead of apologizing as a solution.