He's escalating.
Letting the boys loose was, essentially, passive. He didn't have to do anything. It was all about not doing - not locking the back door, not telling the boys not to run to your office, not running to stop them - a whole load of 'not's.
Now, he's being active.
- bringing the boys at exactly 5pm (to tell you work's over and to start your 'proper job' of mothering)
- shouting to embarrass you and your colleague
It's a gear change. He's actively trying to make you look bad to your employer - making it look as if you're a clockwatcher (finishing on the dot), implying it's you that's interested in your colleague, just all round trying to make you look unprofessional.
He is escalating, his next stunt will be even bigger and you probably won't be able to cover it up. As it is, I'd be surprised if your colleague isn't wondering what the fuck is going on with your husband. So - are you going to sit and wait for the next stunt, or take action now and try to de-escalate him / head him off at the pass?
I think I'd put the fucking frighteners on him. Pretend you're thinking of jacking it in and he can become the sole breadwinner. Tell him he'll have to step up his earnings, do overtime etc. but that'll not be enough to meet the mortgage and the bills, so you might have to leave your home and move into smaller or rented.
If he asks why, lie. 'You are clearly unhappy about my working, I can see that from the last couple of weeks - and YOUR happiness is more important to me than the job.' Paint him into the corner he has chosen to stand in. Then keep talking money.
Watch his reaction. If he is pleased, you KNOW for definite that he's trying to sabotage your job. Then you know you have to get rid. Sorry, but you do.
If he isn't pleased, and start saying the family can't afford for you to not work, then turn it back on him. 'But you've been so clear you don't want me working, pulling those stunts in front of my boss and colleague. You think I'm having an affair!' It might be that he still wants you working, but in a 'little' job. Keep saying he'll still have to work harder to make up the shortfall.
You've said several times, he likes the money you earn. He will not be keen to think of the drop in income, so I think it is more likely he will backtrack. He wants you earning, he doesn't want you to be happy earning. He want's you to 'know your place', which is as his inferior. Never forget that.
I'd start preparing for divorce, because this isn't going to go away. This is about HIS attitude, which won't change. You'd spend the rest of your marriage on eggshells, waiting for his next stunt, putting all your energy into prevention (door locks, blinds, not telling him stuff, etc.). That's no way to live. :(