I used to feel the same way because my SS went through the exact same thing at four. I also felt immensely better when bm started saying she was having the same trouble with him actin out. It seemed dear ol dad, my husband, was the only one the boy was scared of enough to listen to. It's probably got something to do with still being treated like a baby.
I started SS on chores to keep busy and he's improved a lot though still has the occasional case of selective hearing, though I don't know many kids who don't. He knows I love him but that I'm not his mom.
It was really hard because it seemed lik I was losing my place but it's more like you're makin your own. You don't have to be his mom or second mom, just be wooloo.
I hope things get better for you.

Additionally at four we put an end to the phone calls. There's nothing you can say that can't wait four days.

I met my SD when she was 3 1/2, and she acted out like this...DH said the same things..."She only 3..." giving an excuse to her behavior...I ALWAYS pushed back...I went so far as to show him examples of children her age that DIDN'T act out and be mean...Then he went into the whole her not being able to adjust to the situation, blah, blah...I told him that that is EXACTLY the problem and what was HE as the parent going to do about it...Let her just flap in the wind without direction? Her acting out was proof positive that she needed direction...

Being 4 is NOT an excuse for being rude and disrespectful...Your SS is old enough to understand. He might not be able to understand the ins and outs of the dynamic, but as a 4 year old he can understand that being mean is not acceptable...THAT'S YOUR DH'S JOB!

When my DH started understanding what he was supposed to do and tShat SD was being manipulated by her mom, he put his foot down...He nipped her behavior in the bud immediately...IMMEDIATELY...It wore him out for months, but after awhile, she got it...

And as far as BM was concerned, she'd do the same things, too...She'd tell SD that she was on her way to see Disney on Ice or something like that...She was ALWAYS doing something that only appealed to a kid...When SD would get off the phone, she's be more mean and disobedient with lots of crying...DH's solution? He stopped answering the phone...PERIOD...There's nothing in the CO that said he had to take her calls, and truth be told, SD never asked for her, never said anything like, "I want to talk to my mommy"...Soooo...there you go...

So (after BM took DH to court for not answering her calls, and the judge told her to stuff it, as he didn't HAVE to if there was no emergency) started spending a lot of time with her...Teaching her what was and was NOT acceptable as it pertained to our house...He stayed on her when she would be mean and disrespectful to me...she didn't get a break...

If your DH isn't establishing and maintaining boundaries and teaching your SS acceptable behavior, the issues are going to continue, IMO...He needs direction, and the only person giving it (it seems) is BM...and she's the WRONG person to be giving direction in your home...

Kids will pick up behaviours from those around them. A 4 yr old has not got the mental ability to think "She can do all she wants but she ISN'T my mother and never will be". You appear to be putting advanced socio skills into a 4 yr old boy. It owuld be like asking him to understand what happens after we die or how it muct feel to live in the 18th century.

How does your DH treat you? Does he joke with you? Have silly names? Call you Big Butt? This boy is picking up his attitude from someone and it would have to be in your home. Or if he isn't why is he not jumping on his son for being rude and disrespectful?

Also how much sleep is he getting? My kids and now my grand daughter are horrible when they are not getting enough sleep.

Tell the little voice to shut the hell up. Everytime you hear that thought start singing a show tune or your favourite song. You are allowing self doubt to eat away at you.No, you are not his mother but you are another adult in his life that cares about him. I am not the mother of my s/sons but I care so much for them and a damned sight mmore thasn their own mother (in my opinion).

Cut back on the fun activites. Give him cars and a box and crayons. He can colour in the box and make a hut. He gets to watch a DVD when he has been polite and remembered his good manners. Peel back on the trying oh so hard to be what his mother isn't. She is who she is and she is all he knows (apart from you. So she is his 'normal' right now. My grand daughter accepts her father's weird lifestyle becaus he is her 'daddyyy' and she will not hear a word against either of her parents. She has yet to learn her parents limitations. Wait until he is 16 and hates EVERYONE!

I would certainly expect your DH to make sure his son is respectful to everyone especially you. A 4 yr old who makes cutsety smartarse comments may be funny in small doses but in a 7 yr old it is just nasty.

I have a four year old. She sometimes says and does things that, if I were one to take them to heart, would cut me to the quick. When I had my first child, my own mother gave me some great advice: Don't take the things that your children might say or do to personally. You have to be able to remove your emotion from the situation. Kids look to us to see how to react. If we're scared, they'll be scared. If we're crying, they will cry. Your reaction can stand in the way of being able to teach a child at that very moment that his/her actions or words carry a lot of weight with others and that they can either hurt or help. Just like saying "No" to a child, just like not rushing to them when they are learning to walk and they fall and get hurt... With children, it's about modeling correct behavior.

Children are not as self-aware as adults are. They don't have the well-developed filters or attention spans that we have. They're impulsive, they say what's on their minds, they flit from one thought to another... I do not agree that young children are as specifically manipulative. I do believe they are self-centered, but that is developmentally appropriate. Just step back and remember: this is NOT PERSONAL. Don't project your feelings onto this situation. You'll feel much better about yourself and your ability to deal with situations when they arise, if you can do this.

JMHO.