Ah, now you're veering a bit closer to my territory (I'm a divorce lawyer).
If (and I realise it's a remote possibility), you got divorced, the court could and would make whatever order it felt appropriate, which could include taking the view that the trust was set up purely to keep your mum's money out of your dh's hands, and if your dh has made contributions through indirectly funding a mortgage for the balance, has spent money doing your new house up, etc, could rule that unfair and penalise you.
If you didn't put the house in trust at all, you'd get the lions share of the equity anyway assuming you kept the kids and he earns more than you. That would of course change if you didn't divorce till the kids were over 18.
I've just done a case where the wife kept all of her inheritance, then they split the extra equity 60/40 to her. She'd inherited her money 5 years ago.
I'd think seriously about doing a trust deed between you and your dh, leaving the kids out of it.
If, for the sake of round figures, you buy a house for £200k and £100k of that is from your inheritance with the balance raised by a mortgage in joint names and which you'll pay in equal shares, the deed could say that you will get your £100k back in the event of a split plus half of whatever equity is in the house at that time.
If the situation changes (maybe your dh inherits and wants to pay a chunk off the mortgage), you simply cancel that deed and do a new one.
With divorce law, the court will always make whatever order it sees fit with the priority being the childrens' welfare and so will often ignore the fact that a house is in one name only, but if you do a formal trust deed, with each of you taking separate legal advice at the time, the court would have to take that seriously.