Husband arrives home as it's almost time to leave

So I would be packing the car and saying that the car horn will beep in ten minutes sharp, before driving off to friends' home.

On the drive there I would be explaining that being on time with a family is getting home in time to help bathe the kids and pack the car - so at least 45 minutes before blast off.
Explain and apologise yourselves being five minutes late by telling that DH was late home from a bike ride.

Next time communicate more precisely - both him and you.

He should be contactable via phone while out riding, and be able to be traced with the new riding apps that show where he is on a road map - for his own safety, for family convenience and to follow the bike if stolen.
He is a father/husband and an integral part of the family dynamics - part of the well oiled cog and responsible for success of daily living. He should remember that and behave accordingly.

@Loopyloopla So what did you do when he arrived home muddy, 5 mins before you had to leave? Did you go to the lunch and arrive on time, or what?

This doesn't sound like a one-off.

Yep and I’d be telling the hosts the truth about why he isn’t there yet. Men like this don’t give a shit if they defend their wives but they get their backs up if their mates know what a shithouse they are

I’m guessing that this isn’t the first time that he’s done something like this? Really disrespectful to you and your lunch hosts. Sounds like the sort of behaviour from another child rather than another adult. I agree with a PP above, you should have left when you planned to, and he could drive himself/get a taxi. You should also be having a conversation about his odd behaviour.

I agree with this.

He has shown you that you and the kids dont matter, so show him that you are taking him at his word.

Leave without him. Do nothing for him. Let him see the consequences of his actions.

He will kick off about it and at that point you say "Well you didnt care enough to get back in time and care for your kids, so why the hell do you think we should wait for you?!"

As usual @MrsTerryPratchett nails it. Why does he think he can swan about as he pleases while you put all the leg work in?

I don’t know but I would never even date a man who likes bike riding - the Lycra wearing type - I bet he does F all to help with the burdens of family life and you get no time to do your hobby. We live in a beautiful area where lots of men cycle in full gear (not city environment) and When I had kids I realised you never see a woman riding her bike alone. Always men. If you ever see a woman on a bike, 8 times out of ten, she has kids in tow. Never in Lycra, just enjoying her favourite hobby and feeling the winds of freedom in her face!! I suspect your post is the tip of the iceberg..

If you want it to be different you have to refuse to accept it.

I would have just carried on and left without him. He’s acting like he’s the only important person in his life, doesn’t care that you have to do everything and planning getting everyone ready and do the baking thinking he is going to actually be helpful, doesn’t care the kids need help, doesn’t care that your friends have to wait for him at their own lunch. He’s fucking behaving like a rude twat. My parents behave like this and wonder they are always now by default the afterthought - plans are never ever made around them and we don’t care if they come or not but we never wait for them.

I would think this level of selfishness is nothing new so I think you're crazy for putting up with it

I assume you're making the cake and the other couple of cooking. Alright for some. I'd volunteer him for washing up.

Imagine if you did that? He's letting you be the default parent and takes it for granted that you'll do everything. I think you need to have a chat with him about expectations.

He should have been home to help with the kids whilst you got ready likewise you for him also so you'd be on time for getting to your friends house.
I take it you were late due to him having to get cleaned up etc?

You're the default parent and he swans in and out doing whatever he likes.

I assume it's been years of him doing it and you letting him. If you want to change things now, it will be a battle. Can you just bugger off out of the house and do as you please? If not, why not?