Marriage can also benefit you if you have a final salary pension. Not many companies offer these nowadays, but if you've been working for a while (and especially if you're in the public sector) you may have a pension that pays a proportion of your annual salary every year. If you’re married, your spouse could continue to receive the pension amount after you die. But some pension schemes won’t pay out if your partner wasn’t married or in a civil partnership with you.
It's also worth contacting any pension schemes you have, and letting them know who you would like to nominate to receive benefits after you die. Putting plans in place can speed things up for your partner.