If the wife is the primary on the parental duties and she is not getting any sleep, and he is not doing his 1/2, it is on him for the failure.

Parental and relationship work is a 50/50 or even a 60/40 then 40/60 type of deal.

So I would state, if he isn't picking up at least 4 of the nights a week for her and the other bits so she can recharge, then he is way out of line.

Foreplay for her can be simply put as saying, cleaning the babies "bum" feeding it in the middle of the night, cleaning it's diaper, doing all the laundry and household activities so the wife can get a solid 8 hours of sleep a day ...

Secondly, the woman's body has been through hell, so she need to recharge and recover from that also.

On her side if he does this, then after he is done with his parental duties, then maybe she can step up (if not in the mood or able to to do PIV) and give him a "hand" or "oral" or anything to help get him off.

After the work is done and if she feels ok.

If she isn't in it, but sees he is doing it make sure to talk and share.

Once settled in and if helping, then if she still doesn't want to, then either she needs therapy or medical to find out why and possibly therapy is required.

If that has been done or there is a refusal to do so, then couple's privilege on sexual matters should be investigated, or lastly a divorce.

He should also understand going this route drops his attractiveness exponentially because it shows he isn't in it to win it for relationships.