You are, in fact, what many of us need, having come close to the edge ourselves in our own ways. So don't feel bad about that.
Ouch, you have some difficult life circumstances to deal with. I'm a divorce lawyer, so I know how hard the fights around children can be. On the children, that is. Not to mention the parents. On the other hand you are, as you say, on the brink. And for me (your mileage may vary) that means on the brink of doing something drastic that may mean for your children that they don't get to see you again.
Please don't make that choice for them. Even if their mother makes the choice for them and you are separated from your children for some time, believe me, they will come back if you want them to and they will get to know you as the person you want to be. Your children deserve to have that option and as painful as that may be to you in the short term, they are better served to have a parent who is alive and is different than one who was taken from their lives, either by disappearing or suicide, by no choice of their own. It may take time, and time can be a number of years, but be there for them. That will be more important to them than that their "dad" is unhappy, but fits the mainstream definition of normal. Or worse, their "dad" went away some day and never came back.
I see the pain that kids suffer from their parents' choices everyday (I also defend young offenders), and transsexualism or crossdressing has never been one of those problems. Missing, absent, distracted, violent, neglectful, or dead parents is a problem.
Dennis
PS: and I have had clients who are TG or cross dress and I've never had their kids as young offender clients.