Will ( husband is step parent, what happens if he remarries or cohabits)

Jalima, thank you for the link, it helped to read the consequences for remarriage etc.
I will be getting in touch with my solicitor as in addition to the investments belonging to me our house is jointly owned although bought with my money. As you say, I need good legal advice.

A will becomes invalid upon marriage, doesn't it? So, if anything happened to you and your husband inherited, then he re-married his old will becomes invalid.
www.thisismoney.co.uk/money/experts/article-2409754/Is-true-getting-remarried-invalidates-will.html

It would also make a difference if you own your home as joint tenants or tenants in common.

You need careful legal advice if you do not wish your children to be disinherited.
Of course, it may never happen - you may outlive your husband . But you can't be sure of that.

Many thanks to everyone who has commented, it's the first time I've used the forum.
Your overall response has put things into perspective, don't think I was seeing the wood for the trees!
Pippa000, you are correct as is Ellegran we both have our own wills and it would only be mine that would need to change, I was thinking we both would have to make changes. The cost wouldn't be a problem and I would be much happier knowing everything is clearly written in black and white.
Tanith, that's interesting, I will enquire about a new will and see which option is the cheapest.
Elegran, the joint account is only for bills etc, we both have separate accounts of our own and the investments are in my name. They will become my husband's if I die first. The house is our own, I bought our first home outright, our present house was bought with money from the first house being sold before we moved. Again a fair amount of money involved.
Next step is to contact my solicitor and arrange a meeting to discuss the next step.
Thank you all again, I'm thinking much more clearly now.

You say "We made a will . . . ." but you don't really mean that, do you? Surely you mean that you each made a will leaving everything to the other, and so on?

If you have a joint account, then half of what is in it is yours to leave as you wish, and half is your husband's to leave how he wishes.

Absolutely agree with Pippa000

It is actually usually cheaper to write a new will than update an existing one. I would certainly make a new one if I were you that will negate the old one anyway.

I think you have good reason to be concerned. If you die first and your husband remarries, then dies before his new wife, I'm not sure your wishes will be upheld. It will depend on the wording of your wills. Someone will be around on here who will have a better idea.

I assume you have your own will? Why does your husband need to agree to you changing it? I would tell him that you are not happy with the way it is worded and are concerned that your children may not benefit as you wish, then go ahead and get it updated to reflect exactly what you want. I am sure the cost will not be prohibitive and will put your mind at rest, which in my humble opinion is worth the money.