I am glad that you are still here with us, and I would strongly urge you to get help, in whatever way. Friends and family are of course, the first ones I would suggest, but if you feel that you do not want to burden them, then please contact a help line, or a priest, or a counselling service - whatever. A lot of them let you stay anonymous.
In my experience, when you are in that state of mind that suicide seems the only/easiest option, then there is NO WAY that you are thinking of the best outcomes for other people in your life.
You not ever being there for your kids ever again is NOT a better option that you being there broken, but still there for them to be able to actually tell you how they feel and listen to you. Not even close.
You will be far too enmeshed in your own feelings of hopelessness and loss to be able to think clearly. You NEED someone who can look at the 'helicopter view' objectively and bring a new perspective to your mental state. Even a complete stranger who is empathetic can do that. They don't even need to say much - just listen to YOU saying it. The act of talking it out can help on a massive level.
My kids were very young when I went through my patch about 15 years ago. I look at them now and think about all the incredibly wonderful things I would have missed if I was not here.
Go. Talk to someone. Now.