Hello Reikiannie,
From what you describe, it sounds like the Apple ID you share may be causing issues to where the messages should be going to. On both iPhone's, open up Settings > Messages and look to see what Apple ID account is signed in. If they are the same, this would explain why he would be getting your messages. For some additional troubleshooting with Messages, take a look at the first article for some assistance.
If you can‘t send or receive messages on your iPhone, iPad, or iPod touch
https://support.apple.com/en-us/HT204065
Ideally, if you are going to use the same Apple ID, you will want to use it for purchases. For things like iCloud and iMessage, you will want to have separate accounts. This will help reduce issues with messages being crossed. The next article will go into recommended setups for dealing with Apple ID setups.
Set up your Apple ID for iCloud and iTunes
https://support.apple.com/en-us/HT204053
Let me know if this helps.
Take care