I am so terribly sorry for your loss. How devastating to lose a pet that way. It must be so hard having your husband gone on top of everything. I know this may not provide as much reassurance as is needed, but you clearly did not mean for this to happen. Sometimes our pets do unexpected things... We have our usual routine, but then for whatever reason, that one time, they do something out of character. It’s every pet owner’s nightmare for it to end like this. Please be assured that you had his best interests at heart. This was just a horrible, horrible accident.
This will take time. The grief and guilt that always seems to accompany it can get overwhelming at times. Please feel free to post and express yourself as much as needed here. This is a place where everyone understands what you’re feeling.
Hang in there and take care.