Your husband sounds selfish. It was fine for his kids and ex to intrude on your life (and they still are), but now that your son needs your help and is taking some attention away from your H, he is having a little fit.

My opinion as a bystander and biased as a SM says it’s both of you, but mostly him (95% him).

Him: For being a passive aggressive instead of bringing the issue up to you to give you a chance to make accommodations.

You: Your part in the whole fault is for not calling it out and nipping it in the butt as soon as you noticed it.

The petty side of me would put up all the grievances on a piece of paper and tell him to suck it up because you have been on his side through XYZ and the least he could do you is extend you a little grace for a temporary situation.

At this point it would be most important to find a way to communicate your side without your SO shutting down. Maybe counseling to teach him how to communicate but bundle it as a “our” issue instead of a “him” issue.

Have you talked with DH about what is bothering him? I know for myself a lot of times I can pick up on his mood 100%, but completely misread DH's thought process.

You haven't said what your son needs from you. Is it just your time and attention? If so then your husband is probably not used to not being the center of your attention and is indeed jealous. Remind him of all you've put up with for his and tell him to grow up.

Does your son need to live with your temporarily? If so then he is probably feeling territorial.

Does your son need money? Well that speaks for itself, you husband feels entitled to your money. 

We need some more details to know what's going on here. However since you've put up with his kids issues and he's having an issue with taking care of your son I think you need to remind him of this, frankly he owes you and he needs to grow up. You've paid into the bank and he's not letting you make a withdrawal.

My husband can be similar though I don't have any kids that aren't also his. He expects an appreciates me supporting him and he does constantly show his appreciation for it. However whenever I'm the one who needs support it's almost like it doesn't compute for him. I'm the one who provides the support and he's the one who gets it it doesn't often go the other direction. 

You know how some men turn into babies when they get a cold? Some men also turn into babies when they have to share their partner's attention or tolerate being uncomfortable emotionally for a little bit.

while it's too vague for me to say a lot, I would like to ask: when you are putting up with the crazy toxic baggage of his life, how would you have LIKED him to treat you? 
Maybe he does owe you, maybe he should have been better, maybe he isn't being fair... regardless if the situation was the other way around what would you want from him? I am not saying don't help your son. But maybe you can make some time to show your hubby some attention and love. Reassure him and talk to him. Be the bigger person and treat him the way you would want to be treated, not how he may deserve. Your marriage will be happier for it and you can feel good about taking the high road.
that's just my two cents 

hugs

Need more details about what kind of help your son is needing. Not that it entitles your DH to throw passive-aggressive jabs, but it would give a bit more context so we can try and see what is going thru his thick skull.

You both came as a packaged deal. Your DH can't expect you to be a parent to his kids and not parent your own. 

With the shared information, the issue is obviously your DH's.  Time to point out the facts to him regarding the issues iwth his X and spawn Vs the lack of historical issues with your DS.  I would even give him a spreadsheet of estimated hours invested in issues caused by his past and tick any ongoing hours off of that balance sheet as you help your son.

It will infuriate your DH but it will give him clarity that he can STFU and be supportive or he will hear about every sordid historical detail his past has infested your marriage with until he gains clarity and becomes supportive.

Good luck.

Your DH is being a big jealous baby.  You've been there for him and his family for decades and now someone from your family needs you. 

 DH is not talking hardly at all to me today. 

Good, let him be silent and go sulk in his corner! I have a very low tolerance for grown men's baby sh*t.  

It's borderline abusive I'd say for him to want to separate you from your own son/family- especially if it's just time with you.  I would suggest immediately counseling or would strongly consider leaving someone this selfish and malicious.

certainly his issue.  My dh was like this too.  My son was never an issue and smooth sailed through teenage years etc , while DH's son caused so many problems and dealing with the toxic ex year after year!   I put it down to the fact he was always pissed off because he knew his son was a problem and jelous that i breezed through with my boy , now 19 and doing very well. his son is still the devil.  Just go about your day doing what you need to do and brush him off with "you just worry about your kids"

I think he's a little jealous. He's used to having you all to himself and dealing with his kids and his side of things. Now because you're helping your son it's taking some of your time and attention away. My dh acts this way at times. My kids are older than ss11 and my oldest daughter really needs help now. She seen her boyfriend get murdered right in front of her A few months ago. This has had a terrible effect on her and it's led to a lot of problems. Dh is mostly understanding and doesn't mind me helping her but there's been times I could tell he was jealous. I deal with his nasty entitled child almost every weekend and needless to say it has made me resentful. He's being helpful now but I can't forget when he wasn't. Like you said you're gonna help your son anyways. He'll get over it and if he doesn't then too bad. You've dealt with his side. Tell him now it's his turn because you stood by him. I hope everything works out good for your son. 

Hey Sandybeaches,

Your husband's unjust behaviour becomes even more egregious, taking place while you’re involved with your son’s issues and need a clear head to cope with it all. Instead of providing comfort and support, your husband is adding stress to an already taxing situation. Your son, poor fellow, is probably sensing the discord surrounding his visits and feeling like an intruder.

In your shoes, Hon, I’d be burning with resentment! Quite frankly, having read your previous posts, I'm baffled as to why you put up with such a selfish, abusive (and yes, 'the silent treatment' is abuse) man and his horrible baggage. You're a good person and deserve better!