One of the things - as painful as it is - that you have to learn is that you can't control other people. It sounds like your DH hasn't done the work to heal from his past, and instead expects others to cater to his rigid, inflexible lifestyle. That isn't something you can fix.

What you can do is let your DH know that his behavior hurts you. What you can do it go into therapy for yourself and recommend couples counseling for you both since you're unhappy in your marriage. My guess is, based on what you wrote, is that SS is the biggest sore spot in your marriage, but not the only one. You're likely able to deal with the other parts better because they aren't as bad without SS there as a catalyst. That doesn't mean things are GOOD. It just means they aren't as bad as when it's bad.

There are other options that don't involve fixing this. You can disengage from SS and not be involved in his care. When your DH goes on a rant about SS, just stay very neutral in your responses (e.g. "that sounds like it sucks, dear, ready for dinner?"). If he starts being an arse to you because he's mad at his son, very plainly tell him that you're doing as he as asked, but you won't put up with being yelled at because he's frustrated. If he can't handle his own emotions, then he and SS can go elsewhere until he cools down.

If that doesn't sound appealing, then you'll have to reconsider your marriage. There is no magic phrase or trick that fixes these situations. If you truly mean no harm to him and his son, but he interprets everything you do with malice, then the problem is with him, not you.

One question you can try asking, which may give you some insight or cause him to think through his own thoughts, is:

"DH, if you think I am trying to harm your son, then why are you married to me? Why are you putting your son in harms way for sex and companionship? Either you're a piss-poor father by exposing your son to someone harmful to him, or you're a piss-poor partner for thinking I want to hurt either of you. So which are you, because you can't be a good parent and remain married to someone who hurts your child, and you can't be a good partner while baselessly accusing your partner of being horrible when it's simply not true."

Seems to me that you two did not discuss your role when you married - you assumed you'd be an equal parent, and he did not agree to that. Quite honestly, he does have the right to parent his kid without your interference, and to not have you be an equal parent, since you aren't one.

None of the things that you describe him doing are "controlling", unless they are taken to an extreme - sounds like he's actually parenting his son, unlike many men on this board. Could it be that you want to be a more permissive parent than he is, or is there more to what he's doing with his son that worries you?

You two should really get on the same page with parenting before you have your own kids, if that's possible to do.

Your DH wants you to disengage, I would take him up on that.  I commend you for your good intentions and you are probably right that things would be better your way.  But, he is the parent.  I would step back and let him do it ALL.  I would assume the "fun aunt" role.  My DH had a stepmom he didnt get along with, either.  I think that colored his view of my role.

You don't have kids yet.  I would keep my eye on how DH parents.  You are the only one who can decide if that would be how you would want your kids parented.

Good luck.

Sounds like you mean well, but like so many other SMs, its coming back to bite you. Disengage. Believe me, you will be SO happy you did!

I agree with those who recommend counseling. I also didn't see if you said how often SS is in your home or how involved BM is. To me (and I am not you), disengagement would be more possible if it's every other weekend. But if it's 50 percent or more that the kid is in your home, i can see how hard it would be to not be part of his relationship with his son.

It sounds like your DH is kind of overbearing and controlling. If that is the case, and your DH is willing to do *all* the work of parenting him, i also think disengagement is more possible. But again, i'm not you. Whatever you do, do not accept a situation that gives you responsibility but not control. Example, you are responsible for watching the kid, transporting him, or basically any work of raising him but no say in how it's done. 

Another thing is, do you think your husband will be this controlling of any bio kids you have with him? That would be a major issue as well. With only a stepson, you can leave this situation behind and start fresh, but if you have kids with him, will he try to control or alienate them from you? Will he undermine your authority with your own child? Counseling may help sort this out. 

Please hold off having children with him until you resolve how you are going to jointly parent a child you have together. This line stood out to me, "...but he needs things a certain way or he gets angry..." Does this apply to many aspects in your life? While everyone wants things "their" way to a degree, the normal response in a healthy relationship is not anger when you don't get your way. How does he express this anger? Does he get angry with his child and with you?

I agree that counseling definitely is needed. There is strain in your marriage that needs to be addressed. Also it might not be so bad to disengage from being in a parent role. This kid has two parents. Be more the cool aunt and develop your own relationship with the kid that he won't have with either parent. 

I never got involved in parenting my SS from a previous relationship he was just my buddy. I have a similar relationship with YSD I am the advice giver, but do not get involved in parenting or how I think she should be parented. She tells me things she will not tell anyone else.  It has made us much closer than before. As far as OSD goes I don't want to be anything to her and I am happy not to be.

It is for your DH and the BM to make decisions on how this child is raised. Rules set when a child is young are a great idea offering a child stability and assurance.  A child that doesn't learn that parents are in control and can be trusted to be consistent at a young age generally has trouble later on . Your life will be much easier if this child is aware of the rules and they are consistent when at your home. A father who is strict, caring and consistent is not a bad thing.

I agree that the rules and consistency are a good thing. But, on having all decisions made by her husband and the BM - i disagree, especially if the child is in OP's home half the time or more. Raising a 3-year-old takes so much time and energy. The household pretty much revolves around the child's needs. Complete disengagement and allowing her husband and the BM to make all the decisions make OP basically a guest in her own home IMO. 4 nights a month is one thing, maybe i could let go and just plan to do other things and be other places. But any more than that, i think OP should have a say in what goes on in her home.