so sorry for you and cody
I know all to well the pain of having to put them down. My Molly was a rescue, she was the product of a divorce, the husband didn't want her but kept her just so the wife couldn't have her and kept her caged for 18 months. My daughter was dating this guy's roommate and she saw Molly. She told him if he didn't give her the dog she was going to tell me and he'd be in big trouble as I volunteer on the animal abuse website. So she said "take the dam dog or I"ll shoot her" Course once she got the dog she brought her home to me. I'm not even going to get into the condition she was in when I got her. But I took her in, cleaned her up and got her healthy and fell in love with her. I taught her what it meant to be a dog, she had no idea what toys were, didn't know how to play, she was a pathetic sight. But over time she came out of her shell and was the best girl ever. I had her a short five years then took her for a routine checkup and found she had lymphoma. She lived five weeks after that. I promised her that the last thing she saw would be my face and the hardest thing I had to do was take her to be put to sleep but I stayed with her to the end. She will be gone a year on the 25th of this month and I still miss her. So I know how you feel. But it will get better. We never get over loosing them but we learn to live without them.
Your Cody is with my Molly probably playing together as we grieve for them but with time the pain will lessen but never entirely go away