AMEN Gecko!!
I am from a divorced family and I have step parents. I also am a step parent.
One thing I have had to realize as I've gotten older had more parenting and step parenting experience, it this.... We are all different and we all have different perspectives on things and we all have different opinions on how the family dynamic should work.

Your wife is looking for acceptance and acknowledgement. Acceptance and acknowledgement from your children and acceptance and acknowledgement from your Ex-wife. It's simply not going to happen. She is also looking for acknowledgement from you! I think your wife is being unrealistic. I also think that you are both to blame. You didn't establish boundaries at your home. ALL children need boundaries and especially in a (step)family home. Your wife also needs to respect the fact that your children are in the middle. They didn't ask for this and they didn't marry your wife, you did. True we don't pick our parents, but they had no say in picking your spouse, and your children probably feel like they are betraying their mother when they are with your wife (their step mother) and part of that is more than likely coming from what they are hearing from their mother (you cant control that). I bet if you asked your children, they would tell you that they don't feel like your wife loves them. I don't care if you're 17, 12 or 42 you want and need to feel loved. Your wife needs to understand that. Your wife doesn't have to like your children but as an extension of you and her own children (they are half siblings) she does need to try to understand them.

17 and 12 are plenty old enough to have intelligent (semi-adult) conversations with. You may have to take a step back and have a do-over. Maybe the entire family (except the ex-wife) needs to re-establish the family as if it were just starting from the beginning.

Once again, I appreciate the comments from everyone. All of you are right concerning boundaries, acceptance and acknowledgement, and what role my wife should take as stepmom ... vs. what I probably thought she should take.

My oldest daughter (from my first marriage) has always been a sweet, caring, and upbeat individual - even after the divorce. I am starting to see a shift in her behavior as she reaches that magical age of 12. Perhaps its mostly the influence of her peers and general shift to being a teenager. But I think its also that she now has a better understanding of the needs discussed above: acceptance and love. And unfortunately she hasn't received what she needs from me and my ex-wife as of late.

This is my fault and I do accept that responsibility. I DO want things to improve and I agree that we need "a do-over". Whether my wife and my older children agree with this remains to be seen.

The insight provided by those posting is helpful. I guess I've been too blind to see some of it and to weak to do anything about it. They don't give you a manual on this stuff (at least I didn't get a copy).

What are your plans concerning a do-over?

I DO want things to improve and I agree that we need "a do-over".

---> You CAN'T do a 'do-over'. Once something is done, you can't unspill, unsay, unwreck, uncut, unglue and so on a so forth. And while you can 'undo' a seam you have just sewed or a a few rows that you knitted or crocheted...the fabric, the yarn, the thread...it's not the same, it's already been changed by your actions.

---> What you CAN do...is move forward. And hopefully, with a favorable outcome, but there is no guarantee. And it a constant work in progress until that progress becomes habit and that progress can take time. It takes just seconds to wreck a vehicle, but how many hours...days...weeks does it take to repair it? And then...it may be 'AS GOOD as new', but it's still not 'new'.

There is nothing wrong with having two sets of rules between the houses, if your wife wants the kids to keep their clothes picked up and put away in HER home, then that is how it should be. It will not hurt the older kids to learn niceties such as saying please and Thank You, they are not owed anything from her and if she does something for them a simple Thank you may go along way. and last if she feels that her little ones are in danger from something the older ones have done, I do not BLAME her for kicking them out, after all they are her babies

So, it is okay for a step Mom to not allow her step kids in her home for no reason? The only real reason Dad gave was because the kids don't put away their laundry.

My kids Dad refused to see our Daughter for years. He would pick up our son, but not our daughter. He insisted she get counseling but refused to go with us. Coulselor said there wasn't anything wrong with her. Many years later he told me that his gf at the time was jealous of the time he spent with our then 3 year old daughter because she looks like me. So, because of that woman he has no relationship with our now 10 year old daughter.

How about Dad quit blaming bio Mom and step Mom. Talk to step Mom about what her expectations for her role in his kids life. Don't expect bio Mom to thank step Mom (stupidest thing I've ever heard, btw). Work together on developing expectations for their family. Don't expect bio Mom and step Mom to have a relationship unless both sides are agreeable. How about put his foot down and don't throw away his first set of kids because his new wife wants to sleep in the floor of his baby's room when she's preggers? How about marital counseling for him and her?

How about talking to her OB/GYN about her seemingly odd behaviors and possible paranoia? Don't want her to end up being one of those women that kills the kids when he's at work because a voice told her to.....

How about getting fixed and/or using birth control? Stop having children with the step Mom until you get things figured out.

First of all I was not talking about a Thank you from the bm, although if SM does something special for her kids, it would be the polite thing to do, I was speaking about the older set of kids. Sounds like SM set rules and older kids didn't feel as if they had to follow them because the rules are different. Did you ever think that maybe there is a reason she fears for her little ones safety that we are not hearing?? I know of a case where the first set of kids were abusive to a toddler and that child wound up in the ER, when asked ( they were young at the time) it was because bm told them to hit the baby to teach him not to steal their daddy's love from them.

I know of a case where the first set of kids were abusive to a toddler and that child wound up in the ER, when asked ( they were young at the time) it was because bm told them to hit the baby to teach him not to steal their daddy's love from them.

---> I don't think the above has any bearing on the incident with the knife, I think it is probably more of "the straw that broke the camel's back"...just one more instance in a long line (over many years) of instances in which she was treated as a 'second-class citizen' in her own home.

Sounds like SM set rules and older kids didn't feel as if they had to follow them because the rules are different.

---> From what the poster said in his original post, I would say it is more of a case that the father simply didn't enforce ANY rules in his house.