With one child already and another on the way, I understand why you made the decision you made. Your wife could really make your life miserable and Coda's life miserable too. If she really hates dogs she may have treated him badly while you were away. It's just a shame she is depriving your children of having a dog, especially a boxer since they are so good with children. At least you know Coda has a good home now where he will be loved by all.
When my husband and I met I had two 5 yr old boxers. I grew up with dogs, he had 1 as a child. At first he didn't really care too much for them, but he treated them well. They are both now gone, just in the past year at the ages of 9 and 10. When circumstances arose that we had no choice (due to a brain tumor and enlarged heart) that we had to say our goodbyes, my husband was crying just as much if not more than I.
Maybe in a few years when the kids are old enough to help care for a boxer you can get another. Maybe it will be your turn to make the call on that decision. Marriage is give and take, especially when there are children involved.
Goodluck to you,
Christy
BTW, we have 2 dogs again. My husband picked a flat-coat retreiver and I have a boxer-beagle mix. Both from local rescue organizations. He likes them both plays fetch with them, takes them for walks. Maybe your wife was a little jealous.