MidiP, of course you can't dictate how he parents, but how about sitting with it awhile and see what's happening? Do you think he is generally alway irritated with the children, or is he taking out frustrations on them, or is he projecting his own issues onto them, or is he someone who doesn't particularly like children...
Maybe after some shrewd observation time (and noninterference) you can approach him with your concerns or ideas. Definitely LEAVE IT for a calm and open moment, and not in the middle of a down period.
As for the bringing up of wounds inflicted, it's perfectly normal, but you do see how unproductive it is. Try to see him as a wounded human being with pain and suffering and fears of his own, and come at it from a compassionate point of view. You know he's not trying to hurt you or NOT contribute, right? So look deeper, see what he's afraid of, what he's crying out for, and try to see him as another person in the world, struggling.
Not to downplay the courage it took to be alone with all that's on your plate for so long, but remember - with not thinking coming back was an option, how much courage it took for him to make that move. And it was out of love for you and the children.
It's so hard, MidiP. Don't be so hard on yourself, and try to relax. There will be all the time in the world to talk about OW, abandonment, etc. NOW is not the time - now is the time to enjoy your honeymoon (and your new underwear). Ellie must be so proud!