No you are not wrong and your wife is taking advantage of your kindness. Re-evaluate your marriage and really consider if this is how you will continue living. Your wife not once but twice approved the SS to move in without your consent and with that he came with his fiancee, daughter and a dog. Where is your wifes respect and consideration for you in all this?

If things don't change I'd really think of moving out. Your well-being and sanity come first and isn't worth losing for anyone.

Oh my gosh. She knew you were unhappy when SS lived with you before. Did she think you’d welcome him back with girlfriend, baby and pets? Or does she think she is so magnificent that you will endure anything to be with her?

You’re being used and ignored. That would be intolerable to me. You need an exit plan. 

You are being used and exploited.

Does your wife work?

Then don't get angry.  Call the sheriff, have them escorted off of  your property and served with an RO keeping them away from your home, and when your bride blows her stack.... Tell her it is her choice to get angry so she can get over it.

Nope, no adult child with a wife, a baby and a dog is going to move into my home without my express permission and invitation.

Inform DW that if she takes issue with it she can move out of your home and in with her adult son and his family while your baby stays with you.

As the major financial player in the home/marriage... you have the final say over who consumes the financial support  you provide to the family in the event there is a disagreement.

I would be livid if any of my stepkids move in! And with fiancé, baby, dogs...oh HELL NO!!!! Make it unbearable so that they move out! 

You are being way too passive here.  It's your choice to be angry?  "Yes, I am punching you repeatedly in the face, but it's your choice to be angry about that!"

Let your wife know that you will no longer pay for the freeloaders, she can pony up for their share of expenses.  Or better yet,  let her know when they have to be gone or you will be.

I agree with the other posters, you need to say enough. Rags is right if it makes her angry that’s her problem and she can move out and take all of them with her.

Even when my adult skid lived with us his gf was not allowed to sleep over, if you want to place house get your own place was my rule. If my skid that he was adult enough to have a kid then he needs to be man enough to support his child on his own, otherwise double bag it or don’t have sex. And know one deicides that any pets or animals are going to live in my house except me and my spouse. If one spouse is opposed then the no wins for the sake of the marriage.

whatever you decide to do I wish you luck, you have a hard road ahead before it can get easier with whatever choice you make.  

You have all the power here sir, you just have to be willing to make a show of strength big enough to show you mean business.

Your wife thinks she's the one in control - because you've allowed her to be. But the truth is, you are the head of your household,  you control the purse strings, and the time for talk is past. Action is required now.

• Using stealth, remove all important financial and personal documents from the home.
• Cut off the money. Remove your wife's access to all bank accounts and credit cards. Close joint accounts, open new ones at a different bank.
• Get a P.O. box and submit a change of address to the post office.
• Cut off all luxury items like cable tv & internet, suspend all cell phones but yours. Disable all other vehicles belonging to you, and remove the keys. 
• Give the leeches a written 30 day notice to vacate (or less if it's allowed in your state).

Once you've given your wife the Shock and Awe, tell her she either puts the marriage first or she can leave with her mooching offspring. One way or another, your life will get better.

Grow a backbone, spine, some balls. 

I would go directly to your SS... and his GF.. give them legal notice of eviction.  I would also suspend internet.. cable tv.. I would also cut off your wife's access to your money.. until you are sure she can be trusted not to siphon it off.

Tell her,, you are done being angry.. because you are taking the control of your home.. she is no longer driving the bus... if she doesn't like it? she can leave and set up home with her son.. good luck all of you living on your salary.

So you married a woman with a child's mentality and you're surprised it's chaos? Why did you marry a problem like that?

Did you ever open your mouth and say NO? You make it sound as if this was all happening while you weren't in the house. When SS started rolling through the door the second time with all this baggage, broads and dogs, did you just sit there and watch?

After the first miserable time hosting SS, when you got the break of a lifetime and he moved out, you never told your wife, "never again?"

Judging by what you wrote, all this stuff just kept happening around you and you didn't even mention that you can't stand living with SS? What did you think would happen?

Don't be conflict avoidant and then boo-hoo about your miserable life. You had a chance after SS lived there the first time to put down your foot and say "Never again." If you didn't, I guess you have to live with it.

And I'm sure there is more to the story than posted.

It seems like you are always working, opposed to your wife's 20 hour per week minimum wage job.

I'm curious; if she has a childlike mentality, how is working for the wages she earns beneath her earning potential? What degrees does she have?

In theory, it is always easier to tell someone, "I would ..." but we have to take into consideration, that we do not know your style. SOme are very non-confrontational and conflict avoidant. This just makes for misery. Boundaries must be in place. Creating boundaries, and confrontation need not be miserable. This can be done with tact and grace.

I have a feeling you must have been at work when the move took place. 

For sure, you must take control of this situation.

I do not feel YOU should be the one to move out, whether the house is in your name or both of your names, you must talk with your wife. If she refuses to listen, I feel tough love is needed. They all need to go since they are one big happy family. Believe me, if you give your minimum wage earning wife the ultimatum, and cut off her gravy train, she will most likely have an instant attitude adjustment.

Give us the update when you are able, and good luck.