The trust fund money was for you alone and should be for youself and your kids to do what you please. Not in a pot or joint account. IMO
Imagine a man being told this. Pigs would fly.
Look, OP, I think the really important thing is for you to think about how this would feel to you if, in a few years and for whatever reason, you were in a more dependent position in the marriage, and your DH (as he will be) got a medium-sized bonus and kept it for himself.
Are you always going to want to joint savings even if he ends up earning more?
Are you always going to want separate debts?
Are you always going to be happy with someone keeping £500 to treat themselves, when other things are not covered (and yes, I’m talking about debt - married debt is just debt).
If so, great. If not, remember that this will be the precedent you set.