Life insurance is a good idea once you realise that your death could/would have massive financial impact on the other.
Example. SAHM and working DH. If he died, I would have a house - great - but no money to pay bills or the mortgage, and I don't have the earning potential to be able to earn bills/mortgage AND childcare bills (no family either.) So I'd basically be screwed. I wouldn't be able to afford the funeral either, or the funeral fees. Even with a bit of a lump sum from his account, it would run out fast. I'd still have to sell the house I couldn't afford to upkeep.
Solution: life insurance. Now if he dies, I would have enough money to pay off the mortgage then either keep or sell, and enough money to choose work, childcare or both. We survive.
Scenario two, I - the SAHM - die. Now working DH has to choose between childcare and work, possibly also can't afford both, money becomes tight, probably has to leave them in childcare for very long hours well into the evening, into the night, maybe have to move hundreds of miles away for his relatives' support. Life probably very miserable and poor.
Solution, life insurance. Now if I die, mortgage-free DH can choose between a balance of work and childcare solutions, keeping life stable and his future and earning potential, thus ability to care for the family, intact.
Basically once you share property, and more vitally children, you need to figure out what would happen without one of you. The earner and the carer areas are each just as vital. You can't earn without childcare, you can't buy childcare without earning, you can't pay the bills or eat without earning but... back to square one.
We have quite high insurance so the surviving spouse can actually live a merry old life without the other. Might as well enjoy it!