It's likely that you pension fund will be your second largest asset, if not your largest asset, so it is definitely something to consider.
At pension age, your accumulated pension fund will be used to purchase an annuity for the rest of your life. The pension payable will vary depending on a number of things including for example -
^your age at retirement - life expectancy will be different so the company providing the annuity may expect to pay your pension for say 30 years (from age 60), 20 years (from age 70),
^your health - if you can prove ill health/terminal diagnosis to the annuity provider at the time of retirement, then you may be able to attract a higher annuity rate
^your sex - females have a longer life expectancy than males so attract a lower annuity rate, two married men could expect a higher pension than two married females even if they have the same accumulated pension fund,
^joint life or single life annuity - a joint life, longest life annuity will attract a lower rate of pension than that of a single person where the annuity will cease on death,
^guaranteed period - a person may choose to have their pension guaranteed for a fixed period, say 10 years whereas the norm is 5 years, something to consider if annuitant has children who are still dependent,
^the annuity rate available at that time,
^whether you choose the option to index link your pension, perhaps a fixed 2% rate of increase or the annual inflation rate
Since you have children, this would not be something to be done lightly, what about your other assets? What about a miraculous recovery? What if one of you falls in love with another person, demands a divorce and half the matrimonial home? What if someone claims the marriage was never consummated? The entitlement to the spouse's pension might rest on getting married before the pension commences and the person actively opting for a reduced joint life annuity. If you were already 5 years into retirement before receiving a terminal diagnosis and marrying at that point then it might well be that the spouse would not have any entitlement to a residual pension.
I am not qualified to advise, you should seek advice from a Qualified Financial Advisor before embarking on anything that might adversely impact on your children.