Why am I receiving text messages from me iPhone 4S

Basics: my husband and I share an AppleID. He has a 4 and I have a 4S, and both are on the latest iOS.

My name is Megan and his name is Steve.

About three days ago, whenever my husband texted me it would show up as if the text came from me. So instead of saying that the text was from Steve Jones, it said it was from Megan Jones. It would show up as read, be in a green/blue text bubble, and be on the right side of the screen. Incoming texts are always grey and on the left.

I started playing around with it and now he no longer receives texts when I send them to Steve Jones. If I respond to his Megan Jones texts, he'll get em.

This morning he texted his mom and she responded. I was able to see both his and her texts on my phone and what he sent came from my name.

What is going on? How do we fix it?