You should check into social security benefits if one of you dies. My guess is the surviving spouse and surviving children would receive in the order of $1,800 per month if one of you dies as long as the kids are under 18. (you'll have to check and not sure what country you're in?)
20K per year in SSI is equal to about 500K in insurance, assuming the 4% wishful SWR.
Also, note that about 85-90 of surviving spouses spend all the life insurance money within the first 18 months. (please don't anyone ask me to fact check, it is close enough for this discussion)
With that in mind it is more important to set up a decent trust that the life insurance would go into upon death. The trust should be structured to invest in something like the S and P 500 with a 4% draw down and a trustee wiling to administer for less than 1/2% per year. You should have this set up anyway in your will if you should both die.
Really life insurance is something to consider after the trust, will, guardians and other items are in place.
Then if you decide to purchase life insurance look into bidding out a 10 year term policy.
http://www.mozdex.com/life-insurance-by-age.phpIt looks like DH could find a 500K 10year term for around 500 per year. The dirty secret about life insurance is that people seldom keep them for very long and that is why companies can make money on them.
Your short term focus should be on the trust, will, guardian though. IMVHO