I agree but think you need to FIRST see a solicitor quietly on your own.
THEN have a "put affairs in order" blitz - at least, that's how you spin it. And you won't be lying, but you will be quietly hoping that the unblinking stare of the solicitor advising you both will induce him to sort things out properly.
Ideally? At a guess (not a lawyer but put affairs in order some years ago).
Marriage or civil partnership (same thing except you can't sever a CP for adultery, but you just call it Unreasonable Behaviour so, same thing really!). Avoids IHT and while you're still alive, can be used to reduce CGT too.
LPOAs for both for finance and for health.
Wills set up so that when one partner dies the kids get left something (possibly in trust with the other partner having a life interest) - this is to deal with the situation where one partner dies, the other married, doesn't make a new will, old will invalidated by marriage, remaining partner dies and new spouse inherits the lot and kids can go whistle.
Right now, if you nominated the kids as your death-in-service and pension beneficiaries, that might be safest. See bit above about marrying after partner dies.