Troucul,
I am in an unhappy marriage with two children and I feel exactly like you do when you ask why you have to be the strong one. Maybe it would have been different for me if she hadn't explored the possibility (hell, let's admit it, she actually tried) of having me locked up in a mental hospital.
Another poster asked how people can fall out of love? How do you fall in love? Now reverse the process. Earlier you spent lots of time with s/he. You were motivated to do special things for this person. What they said and did mattered.
Throw in time, the growing impermanance of things around us (I have cartridge pens where I replace the ink holder, not the whole pen, but it's cheaper nowadays for Bic or whoever to make a whole new pen than just a refiller to put inside the old pen shell, as one example), money worries and working more and more hours to make ends meet, less free time, and emotion gradually dies off, like the embers of a campfire. Sometimes the flame can be fanned anew, but other times, you're better off leaving.
Children will be hurt if they (1) are made to feel they're the reason why or (2) are forced to take sides in a loyalty battle. My advice there: if your wife does that, never reply in kind. Tell them you love them and people sometimes just can't make a go of it. They'll draw the proper conclusions on their own.
Ask yourself this: if you feel suicide is a distinct possibility, what will hurt them more--if you reunite with your wife, the children think things will be better, and one day you take your own life and they're devastated, or you leave, and keep them in your life while building a new one? And if she's a vengeful type, what might she tell them about you after you're gone that they'll think must be true (look what you did, they'll think) and you won't be there to rebut her?
I'm planning on starting a thread in Personal Experiences asking what I'm letting myself in for as far as stress during a divorce. You might want to read the answers I get. May help you make a decision.
I won't say you should do this or not do this, but it's obvious which side of the question I come down on. It's just too easy for those of us who don't have to suffer from bad advice we give out to give it out!
Good luck in whatever you decide. And bro, you're getting counseling right here. We don't have degrees in the field (most of us) but we can empathize far more.