4 times a week for 2 hours with a toddler and a 6 year old at home and at dcs bedtime?
Hell no!
He's behaving like a toddler having a tantrum! Is he really that insecure he can't go the gym alone? How pathetic!
You need to sign up for something that's 4 times a week for a while! Doesn't have to be exercise (although it could be) but give him a taste of his own medicine!
He's absenting himself from the hard work of parenting. Let me guess he's simply pouting at dcs bedtimes now and of no use at all?
He needs to grow the fuck up!
Guessing he also did sod all when they were babies?
My ex (not a shining beacon of fatherhood!) used to exercise at home of a morning (army expected to maintain a certain level of fitness)
When dd was a baby/toddler he used to "use" her like a free weight which she loved and found hilarious and was something of a bonding thing for them then. As she got older she used to "exercise" with him which consisted of either weakly copying him and showing him her "muscles" or running around like a Tasmanian devil 
Tell him you both get to have equal down time as you both work - even though your work is unpaid and in the home.
3 evenings out a week each and the 7th date night?
Thinking it would be a very good thing for him to have to parent alone of an evening regularly! Good for him to bond with dc too
Was he definitely going to the gym?
I was wondering this too. Is friend an alibi or an affair partner?
But entirely possible he's just being a lazy arse dodging the witching hour
Can't he run or cycle to work, or use the stairs more, there are ways to keep fit without abandoning ones family
Exactly!
Bring home brochures and applications for life insurance. Tell him if he is determined to commit suicide by junk food they you want enough money to afford a nanny - and maybe attract a man who will be a real father to the kids.
I like your thinking
But that yogurt was the final straw
I totally understand that
The kids will get over the early years sleep issues but your H will remain a selfish petulant arse for years.
Prob true