Beachcomber wrote:

.......and a lot of political ass-kissing to get his current position...... 

I had to smile at this part of your post 
Wecome to the best forum Beachcomber    you're in the right place

 

Welcome, Beachcomber! So glad you found us--

Recently I had a similar question, because my marriage was very serene and seemingly excellent, too. And I daily feel the burden of knowing the truth while few others do, and I sometimes crave the ability to tell people (and have them understand, which I think is probably a whole other ball of wax).

My son is 15 (14 when we separated), and both his and my therapist cautioned against telling him the whole story at this point, too. He is much younger than your boys, and I must say that I do expect I will tell my son when he is in college or reaches adulthood, if my husband continues to be in denial and in the closet. However, some spouses do decide to not "out" their exes widely, only to close friends and family, as Janet McMonagle describes on the Straight Spouse Voices podcast. I guess one question might be: do you and your husband feel comfortable telling your sons everything and then asking them to keep quiet about it?

I did tell a close friend and my (somewhat large) family, and they agreed that it might be better to wait to tell my son, but not forever.

Good luck with this decision and wishing you the best in the coming days.

I agree with Walkbymyself, even though I have not told my son the whole truth about my ex's decision that he was transgendered.  What I told my son was that after 35 years of marriage we did not simply "grow apart" or were now "happier apart." I did not want him thinking that marriage was something to take that lightly.  I told him there was an issue that was his father's, and that is was his father's to tell him about, but that I already knew, because I had told his father what I was going to tell him (our son), that his father's response, should our son ask, would be "Some things are private." (I had not yet read what someone recently posted about the distinction between "private" and "secret"--Thank you for posting that!  So helpful!)  My son now knows there is a reason, and he can ask if he wants.   In my case there are also other considerations: my in-laws are providing some money for my son's education, and I don't want to put my son in an awkward position with respect to that family connection. However, I do intend at some point to tell him; I think knowing might give him a useful frame of reference to understand some of the family dynamic that has bothered him over the years but which, like me, he had no way to understand.  Plus, he's an adult, and I don't think it's right to "protect" him--it's a paternalistic (maternalistic?) move that denies him his full adulthood, and reproduces my ex's hurtful decision that he should be the one to decide what and when I knew.  I also think that my ex's desire to keep things secret is all about sparing himself discomfort and owning the consequences of his decision to hide and to abuse his family by hiding the truth from us (thank you Oscar Minwalla, for that insight that the maintenance of a closeted sexuality is abuse!).  
  I did tell my family, and some of my friends, including those I have made over 28 years at work, before I was threatened with legal action because we work together and Title IX protects my ex's "gender identity" (although he is still in the closet!).  When I retire next year, however, I will be having some conversations with the powers that be about why I retired earlier than I otherwise would have.  It was hell to be in the closet with my ex and to be jerked around by him, but the actions of my workplace compounded that trauma, and cost them an employee.  For too long I was the only one who lived with the consequences of my ex's actions, and the time is coming when he will have to own himself and his choices, and stop deceiving people about his motives (for example, he serves on committees to do with women, not because he cares about women, but because he derives a secret sexual pleasure from it; that he earns feminist ally points allows him to preen as if he were a good guy, when I know that what he's doing is creeping on women's experience and secretly appropriating it in his own mind). 
   I have seen enough of the therapeutic community's bucking up of the closeted spouse to know that their advice not to tell is designed to ease the way of the closeted spouse while discounting our painful reality.  It's the old "collateral damage" problem--and I, for one, am not going gentle into that good night!

Beach, OK, if this is how he wants to play it, he better take responsibility for the divorce with his kids. He needs to man up, and tell the kids he has issues, and it's not your fault. I would also use this as a bargaining chip in the divorce, get your fair share and more. 

Believe me, your kids can handle the truth its the lies that they can't handle. Same for us straight wives, we can handle the truth but not the lies.

Be well, my friend, be strong.

I know I can be pretty strident about the issue of talking candidly with the kids -- but I do want to emphasize: this is not keeping a secret like "Mom got a parking ticket she wants to keep secret from Dad."  This isn't just a minor thing that they're never going to find out -- they're going to find out, and the question is, do you want to pick the time and place and present this message in the least traumatic way, because if you leave it to fate, your kids are likely to be far more traumatized by the shock of it.