How do you stop texts coming to your ipod touch from going to your iphone

I have an iPod touch that I just bought. My husband has an iPhone 4 that he's had for a little while. We both use the same iTunes account. Today, I attempted to use the text feature to text my sister, who also has an iPhone. The response went to me, but also to my husband, who was asleep at the time. Is there anyway to stop this from happening?