From the practical/financial side of things , if you "do yourself",, I don't think anyone gets life insurance monies.
Not to mention the fact that your kids will feel that somehow they were partially at fault. That will last a lifetime for them..
Please see our Survivors of Suicide forum if you start to think that way again- or read there before you feel that way.
http://neurotalk.psychcentral.com/forum29.html

It's hard to say anything about the marriage situation.
I have brothers that are healthy and they can't even seem to find a lifelong mate.
I guess try to maintain a good environment for the daughters and make sure they know they are not the cause of any tensions in the home...