Debs, I hope you and DH can sit down and discuss this rationally tomorrow.
But, FWIW, in my opinion when you get together with someone who has some sort of passionate hobby in their lives, you can't demand they give it up because you'd find it inconvenient ..... after all, as a grown adult you have choices, you can look after yourself and walk away if you really don't like it.
HOWEVER when someone decides to become a parent, that decision brings with it huge responsibilities and it's selfish to assume that your life will be able to be conducted exactly as it was before. No-one - male or female - becomes a parent without usually having to make significant changes, compromises or even sacrifices.
To my mind, if you have a hobby - "passion" or not - that should take 2nd place, if necessary, to the family you've created. Obviously, a keen stamp collector may find that their hobby isn't too affected but if that hobby impacts upon your family because it's very time-consuming, very exepnsive or very dangerous - maybe even all three - then a responsible, mature adult should agree to take a step back.
It's not a question of Debbsy being a killjoy ..... it's a question of her and her DH taking equal responsibility for their children. Why should the vast majority of childcare have to fall upon her whilst DH's "passion" completely removes him from the picture for 2/3 of the year ? When would she ever get a break, or an opportunity to "indulge" herself too ? And how about Dad actually spending some quality time with his children ? ..... at the rate Debbsy describes, he'd never really see them at all.
I'm sure Debbsy's not unreasonable, and like most people, would be prepared to give and take regarding "days off" every so often. But as she's pointed out this is totally consuming, it's not even 1 weekend a month but often 3 ! She's not "nagged" him until now, even when she's attended various events on her own, but the new baby isn't hers alone and he needs to be there both in a supporting role for Debbsy and, as a dedicated Dad.
The bottom line is that if he didn't want to give up this way of life, he shouldn't have become a Dad. Debbsy said that they discussed it and now it appears, with the encouragement of his mother, that he has made a unilateral decision.
I think it stinks TBH, and he's hiding behind his mum. I think there's a danger now that instead of this only being about what will happen next year, it will also become extra-heated because Mum's been insulted blah di blah.
I could slap women like this who completely fail to recognise their little boy has grown up and no longer needs mummy to speak up for him. I bet you anything you like that she's waded in now because she enjoys going away most weekends and she can see her little jaunts going down the plughole if he doesn't race next year. Hence her attempt to lay down the law. I think it's disgusting that she's poked her nose in to this extent I really do when it's obviously a matter for you and him to sort out and nothing to do with her.
It's also quite a horrifying thought that if you wanted to go along with your DH to these events, it seemingly always has to be with his parents. That certainly doesn't sound as if you can even salvage a few hours together in the evening alone without them being there breathing down your neck.
Hope he's more reasonble minded tomorrow. Good luck.