The critical illness payout is meant to cover you and your illness
therefore it follows that you should keep the payment.
Bearing
in mind you are
not married, on what basis
does your partner believe he has an entitlement to half of the assets?
On the basis that you are to be the paretn with care of the child
it is possible for you to seek an adjustment to the split in equity (if you
feel this step is required) under Schedule 1 of the Children Act 1989.
You may be able to use this as a bargaining tool.
I suggest you
obtain
legal advice to nip these issues in the bud -
you don't want to agree to anything which is unfair.
Charles