With the shrine photo wall, I'm not surprised SS has the wrong idea about his BM and Dad.

I think it's ok to be honest to a point. Were you married? No. But you wanted to marry Mom? Your mother and I were together a very long time ago and it didn't really work out. The good thing about Mom and my time so many years ago is we had you. While Mom and I didn't get along and couldn't be happy together, the important thing is Mom and I both love you very much. When I met SM things did work out for SM and I and we got married are we are very happy together.

It's truthful without details. It doesn't bad talk Mom or Dad and it leaves no room about Dad ever going back.

Now about that wall, yeah, weird. But Dad can handle these questions enough to satisfy his curious son. They are actually normal questions. What isn't normal is that wall.

Odd for kids to want some sort of fairytale ideal about their parents past? normal.

Ex with pictures on the wall of your DH and her together in a public area of the house while she pretty much has been in a relationship. not normal.

I think it is really not all that difficult to give the boy the right guidance.

When your mother and I were younger, we didn't behave very responsibly. Ideally, it's best if the parents are married and then decide to have children. I know it is hard on you at times because your mother and I were never married and aren't together. That's why I hope you can make better choices when you are older so your kids don't have to suffer for the mistakes that their parents made. Of course, I want to make sure you understand that YOU aren't a mistake, but I think things would have been better for everyone if we had planned things better. and no son, I didn't ever want to marry your mother. I mean, I am not saying I knew I wouldn't want to, but when everything happened, I decided that we were not the best match for each other... but I still wanted to be part of your life, so here we are.

Creepy. And I'm just saying, to me, it's a bit brainwashing to make up memories or push onto children ideas and memories that aren't real about an adult relationship they couldn't possibly remember themselves. It hasn't happened over here, but my DH and BM were splitsville at 6 months and I started seeing DH when he was 8 months. I was in SS's life more beginning around his first birthday. BM wanted DH to go to the park with just the three of them so they could "make memories" with SS but DH wasn't having any of that because why plant false memories?! It'll be interesting when my SS pulls this crap even if it is just to see what BM and DH have to say about it.

I think its normal for kids to start talking about wanting their parents to be together whenever someone or something puts the idea in their heads that their parents are supposed to be together or expected to be together. Its possible it took until he was 11 for him to notice it was strange. Maybe all his school friends have married parents, maybe one of his friends dragged him to church and the pastor said it, or maybe it was something more disturbing like his mother started talking about how she wishes she was with your husband. Who knows? He could have gotten it from anywhere, bringing it up is totally normal.
As for your stepsons statements that his parents were married- while ideally parents are together, its still socially acceptable for them to be divorced. Normally people get married, have a child, and then some of those marriages will later end in divorce resulting in single parents. However, there is still some stigma attached to having a child out of wedlock, and I assume your SS picked that up somewhere. Unmarried parents create social stigma for the child as well, not just the parents, as the child born out of wedlock is technically a bastard, which is never used as a complimentary term. So he probably subconsciously tries to destigmatize himself by saying his parents were married. And when your husband corrects him that they weren't, you SS then tries to justify his own existence by saying, well, its okay that they weren't married because they wanted to be married, so the lack of paperwork didn't matter. Or maybe when your husband replied that they were never married, your SS wondered why he even existed if his parent's never loved each other. At 11 he may not understand the distinction between love and marriage. Or love and sex or sex and marriage. His father says they weren't married and he wonders why his parents had him then. Kids find a way to justify or clarify things and that's probably what he was doing.
I don't think your SS actually regrets that his parents were never married or legitimately thinks there is something wrong with him, because he's never known the world to be any other way. It's also not nearly as uncommon as it used to be and I'm sure he's not the only kid he knows. I think it just came up in conversation because he didn't know how else to answer when put on the spot.
How to handle this is a personal decision for both you and your husband because while its not your kid, you do need to be around him and if he's raised poorly by his parents it does affect you. I would push for truth. Just complete honest truth no sugar coating. The bottom line is that the real world is not a fairy tale universe where the princess marries prince charming and the stork brings them a baby when they're ready. Sex is something people do, sometimes for no good reason whatsoever, and it sometimes results in children. Just because someone didn't want a child or wasn't planning on having a child at that time or with that person doesn't mean that they don't love the child just as much as they would love a child that the magical stork brought married mommy and daddy because they loved each other and wished for a child. Being direct about these simple facts of life is much less likely to result in your stepson feeling like nobody wants him or there is something wrong with him than your husbands chosen handling of the situation- gently glossing over of the issue.
As for your husband not wanting your SS to believe that having a child out of wedlock is okay--- Currently in my immediate social circle I am close to three men, whom I have known since we were barely teenagers. I know their parents and am close with their families. All three of them are single parents, all were never married, and none of them had any intention of having children with the women they had them with. The interesting thing is all three of them come from intact families. Their parents are still married today. Their parents had good marriages. (One of their father's has died, but they had a very good marriage while he was alive.) When I was young I was very jealous of their parents marriages because my parents are divorced. In addition, all three of them went to catholic school and know that premarital sex is definitely not considered okay by the religions they were raised in. Two of them have guilt issues around it.
None of this prevented them from having children with women they weren't married to and didn't love. They didn't do it because they grew up thinking it was okay. All three of them know its not okay and are not okay with it themselves to this day even though this is now their life.
Your DH's refusal to confront this head on is much more likely to result in your SS making the same mistakes then the alternative. Your DH should be clear that he did a very bad thing and it was mistake and he doesn't want his son to make the same mistake. Many children of alcoholics completely avoid alcohol because they saw what it did to their parents. You ss would probably be best served by your DH instilling that kind of an aversion in him to this behavior with the truth, and not allowing him to live in a fantasy world where mommy and daddy loved each other very much. As much as he may like it to be, this is not the world he lives in, so don't pretend.

It is pretty obvious that what SS-11 is "remembering" are either pictures or BM stories. The pictures are bizarre and disturbing IMHO but ... her house... her choice of wall décor.

What DH should have told SS is the facts and the truth. "Son, your mom and I made you together and you are the best thing in my life from that relationship. I did not marry your mom because I never wanted to marry your mom and I am sorry you may have been given the impression that your mom and I were ever married, we were not, or that I ever considered marrying her, I did not ever consider marrying her. That does not change the fact that you are my son and I love you. If you ever hear things that are related to me or the old days when your mom and I were dating and got pregnant with you please ask me about them. I will never lie to you and I will always tell you the facts.. Got it? Good."

Lather, rinse, repeat. Adjust as necessary as BM's obvious manipulation of SS-11 changes because inevitably as your DH tightens the noose around her neck (proverbially) with the truth and the facts and SS-11 begins to mature and change clarity.

Firstt of all, no child under the age of one could recall "his parents taking care of him". It sounds like BM is trying to reassure him that he was conceived in a loving relationship. I doubt she is obsessed with DH, but is rather trying to create a sense of family for SS. Kids a various stages are bound to wonder where they fit in and why their parents are not together. Maybe she can't tell him the ugly parts of the truth.

My SD is 22 and her parents had an ugly divorce when she was 6. BM has been viciously hateful to DH ever since (even though she was the cheater whose affairs ended the marriage). Despite this, SD still keeps a number of photographs around her living room with BM, DH and her (including ones taken since the divorce at things like birthdays, weddings etc). Since I came along there have been no more group photos, but it is quite clear that no photos of me will ever appear in her house. SD walks on eggshells around BM, and maintaining BM's version of family events is her mandate whether she likes it or not. People are constantly working on their own version of history, their own personal myths, and justifying their poor life choices.

The healthiest thing for you would be to first, stop competing for first place in the Mom competition, focus on your relationship with DH and don't let this silliness affect that. After, perhaps affecting your relationship is exactly what wonky BM wants. Or not. Maybe she lives with regret that she didn't keep her family intact and now is trying to pretend about the past. Whatever it is with her, one thing is certain: you can't change her behaviour.

BM's BF must be a little bummed out by the pics but then she probably has told him she was married to SS father. Maybe it's why that relationship is rocky, because she lives in the past.

There was a conversation a while back where the kid said something along the lines of asking his dad if he loved his mom... and SO said something to the effect of Of course he did, and they both loved him.

I was pretty hurt, and asked him why he would say that... SO said that he thought it was better for kid if he thought mom and dad loved each other.

I asked him in what world he thought it was a good idea to tell his child he loved another woman when he was with me... I told him that if his kid believes his parents love each other, he will do everything in his power to make his parents get back together, and that includes trying to push me out - so I told him that if that's what he wanted, to go ahead and keep lying to his kid but that I was out, I wasn't going to put up with my man saying he loved another woman.

Every now and then kid asks the same type of question... and SO has progressed - at first he told him he loved her a long time ago... which he never did and I called him on that, too... to simply answering mommy and daddy love you. I don't know what BM tells kid, and I don't care, but SO will (now) be honest with kid about the way things happened... which was that it was a short fling which resulted in pregnancy. Of course it would be put more delicately than that, but it won't be romanticized under any circumstances because he doesn't want kid to think there's any hope of them getting back together.