I would really think about how long you would need insurance. Your kids are a bit older, if you don't plan on having anymore, if you kicked the bucket today then they would need help for what, maybe 10 years? You have a mortgage and expenses but what would your family do if you went, would she move in with her family, or want to stay in the same place? Would she get a job or want to just stay at home and tend to the kids? If they are of school age is there any reason that she couldn't continue to work? I think you said that you get 2 times/salary for your normal office job, right? Is that not enough to float them for a year or so?
Insurance is all a big scam, they scare you into thinking you need it for life, when you really only need it when you're in your lowest point in terms of debt and earning power. I have 3 kids, and we each have life insurance through work, just the basic stuff. The kids are 8, 6, 3 and now only 1 is in daycare. We put lots of money into 401k/Roth/post-tax so we are doing well. I got the x7 insurance for my work and DW has x3, but that is because we can cancel it at any time and I really only wanted it for like 3 years. In another 3 years we won't need it because we'll have a decent amount in investments, kids will all be in school so no daycare payments and my wife has family in the area. So really think about the actual situation and where money will come from, if they will move in with her family if they are in the area, and if your DW will work.
Many people get these $1M insurance policies because they want the house paid off, their spouse never to have to work again and their kids never to have to work, but is that the reality you want for your family? I personally want to have them covered enough so in that few year transition period they don't have to sell the house, sell themselves or live on the streets. If you get an additional insurance policy I wouldn't get locked in for more than 10 years, as at that point they'll have jobs or be in college and can take student loans, or in all honest, if their dad kicks the bucket they will have a great scholarship essay and will probably get money for college.
It's a normal thing to worry about your family, but that's what the industry wants us to believe, that if we don't buy life insurance that we hate our kids and family. Try not to get caught up in the hype and really think about expenses after you kick the bucket.