Oh, Hon! 

I would hesitate to refer to your SO as ‘the man of my dreams’ when he allows his children to disrespect you and also ignores you when the kids condescend to visit. On this site, a man who tolerates being neglected by his offspring, while going out of his way to provide entertainment (and an open wallet), is referred to as a ‘Disney Dad’.

Men (and often women) who behave in such a pathetic manner, chasing their kids and determined to forego discipline for fear of the spawn refusing to visit or preferring the other parent, are very unlikely to change. To get a clear picture of where this leads, please check out the posts by Lillywy00; she recently bailed out of a situation almost identical to yours, with the approval and encouragement of all our members.

You must start with a relationship as you mean to continue and, if there is any hope of this one lasting, you’ll need to put your foot down now! Unless you describe your needs to your SO, his pandering to those brats will not only persist but will worsen as they age. 

He doesn't sound like the man of your dreams. He allows you to be disrespected then ignores you. He may be great in all other ways but this is also part of his character. His kids should stay overnight at his house when their CO says they should. That way you will be able to predict when they will be in your home, even if it's more often than it is now. And when they are, they are not to disrespect you. I think you should stop going out of your way for them. Let Dream Man do for his kids, including plan outings and cook and clean up after them if they are too precious to do it  themselves, but don't let them disrespect you and for the love of God, don't let them in your bedroom. 

I got treated "well" by what I thought was the man of my dreams Tuesday-Thursday.... the rest of the week was spent catering, coddling, clinging to his kids and he only did this to soothe his ego (desperately seeking approval from his "extensions", competing with his exwife to be the 'better' parent, and "rescuing" them from the imaginary "suffering" he thought they were experiencing from the divorce several years ago). 
 

In reality the failed prior family knew how to fleece him out of time, money, any future relationship (basically anything that caused him to take one millisecond of time from their attention seeking antics / one dime out of their bottomless pockets)

The skids I had disrepected me in my home by not following simple rules that a normal 2 year old could do  and my ex partner allowed / minimized their behavior when I expressed my displeasure 

So I disengaged from them HARD (left every weekend I could) to the point I had to leave altogether because I didn't want to be punished by his lackadaisical parenting style nor did I want them to be punished for their fathers willfully obtuse actions. 
 

 I didn't want to spend energy enforcing because I don't do gentle parenting like he did and the moment they gave me disrespect/pushback like they do him I would have them shipped off to the nearest (or furthest) disciplinary military school  

Unless your DH sees a problem AND takes steps to remedy the issue....then this will be an endless uphil battle 

A quesion. What makes a failed father, ball-less  man, ill behaved SKid butt sniffing divorce' who repeatedly sacrifices his new mate and marriage on the the alter of martyrdom to his failed family progeny the man of anyone's dreams?

What makes a man who repeatedly perpetrates these characteristics so wonderful?

Love yourself more. Stop serving yourself up on the SParental alter of martyrdom to this failed shallow and polluted gene pool actively led by your DH.  And for all that is Holy, do not pollute your own gene pool with this ..... individual.

IMHO of course.

Take care of you.

Invite yourself to a friend or family member's Christmas celebration or if that isn't possible volunteer over the holiday so that you can be out of the house for maximum amount of time. Let your husband do all the Christmas prep for his kids, decorating, gifts, food etc. while you take a nice side dish and a bottle of wine to a household where you will be welcomed and treated right. 

His children are all minors.. except for one barely an adult.. he should be having a relationship with them.. and he should be doing more than he is to parent them.. to have custody time etc. 

He should also be insisting that you are treated with respect.. even if they don't like you.. they don't have to like or love you.. they are not to be rude to you.

Also.. consider that this is the only life you are going to get.. do you want to spend it fighting and unhappy?  life is too short.. this guy may not be the one for you.

Until we can't take it anymore. Then it's too late. This is common, I an guilty of this also.  There no SP Primer book what tells you to set the tone from the beginning.  
'My SIL when married my BIL who had two kids,  She rented a one bed room apartment, so SK count sleep over. Couch  I guest we called her the evel SM.  BUT SK could only spend like one night.  
He the kids BFhe has responsibilities to his kids, he also have responsibilities to you.  It's all respect.  SK don't have to love you, or like you, but must treat you with respect. It's your home, that you pay fir in money and effort . He must make them respect you.