You and your DH should parent as you want in your home. You already know that BM will buy him a car and pay for all of it, rescue him from working and use it all to alienate your DH, but continue to parent as you see fit. 

Why get him a car if he's so busy he won't have the time to use it? 

Guess it will be time for him to learn about priorities; he will have to pare down his extracurriculars so he can work a few hours, if he wants a car.

When you're an adult you often have to let go of things you enjoy to take care of necessities. If he wants a car he should work and that means he might have to drop an extra activity or two. That's life, you have to balance work and play. I don't believe the sports and activities are justification for him to get a handout. Actually being able to participate in that many sports and activities is already a big gift for him as many families can only afford one or two activities, if any. These things are a bonus, not something he's entitled to have. You are right to teach him he needs to be responsible and balanced, he can't have everything just because he wants it. 

It sounds like you and your ex are on the same page with parenting decisions, which is great.  Obviously your DH and your skids' BM are not, so it probably doesn't matter what you want - BM will buy the car and pay for the gas, maintenance and insurance. 

I don't think either approach is necessarily wrong.  My parents bought us cars and paid for our gas/insurance/maintenance.  They could easily afford it and preferred that we be involved in ECs and devote our time to school.  We did work during the summer but got to keep our earnings.  That was the norm in our area.  OTOH, my DH bought his own car and paid for his own insurance and maintenance. That was the norm among his peer group where he grew up.  As adults, we both have a good work ethic, and I am much better with finances than he is,  so I don't think having a paid-for car hurt me,  nor did having to pay for his own hurt (or particularly benefit) my DH.  It's a parenting choice and I don't think there's a clear cut right or wrong approach.  (BTW, I still have and drive that car my parents bought when I was 16).

Your biggest issue in your home is going to be the disparity in treatment between your kids and your DH's. I suspect your kids have been dealing with that disparity long enough that they're used to it, but I can imagine there will be some grumbling. 

ETA: Your skids do sound very entitled, and I think it makes sense for your DH to ask his kids to contribute towards a car to get them past that entitlement mindset, but ultimately I'd be shocked if BM doesn't provide the car and all expenses while insisting that your DH contribute (which of course he can refuse). It'll be just another alienation opportunity for BM.

At least he is showing interest in driving, mobility and independence.  Bratty didn't learn to drive until 19 and was happy to have Dadddeee drive her everywhere.  Even the summer she stayed here (where she had access to a convertible) she didn't drive much because it 'scared' her.  When really she just wanted to spend a lazy summer getting up late, watching TV, etc.

I think you and DH should stick to your guns; you know that a car is a responsibility and are trying to teach that.  Unfortunately BM will probably torpedo that lesson but that doesn't mean you should cave either.  

She works as a hostess at TGiFridays and is dual enrolled at the college and does the tech work for the plays at our Community playhouse. She has to pay her car insurance and gas and I bought the car. She does seem very busy but pretty happy I would say. She likes the freedom of having a car 

The good thing is that  you and your DH are on the same page with what you expect teens to do.  As others have mentioned.. it can go various ways.. some parents encourage the EC and schoolwork and discourage after school jobs that might interfere with those things.. that arguably are also important for college entrance applications.  BUT.. many families don't do that.. either they can't afford it, or they feel there is more need for the kid to have skin in the game to appreciate the responsibility of having a car to drive.

We actually bought our OSD a car but made her younger sister buy in half.  Ironically, it's actually the younger sister who has turned out  more responsible.. but it was the older girl's lack of responsibility that made us come to the decision to not fully bankroll the younger girl's car.

So... let's say that this kid truly has some talent for playing a sport and potentially could get scholarships to pay for all or part of his college expenses.. along with his strong academic performance.. I mean, I could see letting him maximize his sports performance and not require the job if the goal was to make him more likely to be recruited to a college level scholarship opportunity.. where making him go work the piggly wiggly would take from that effort and possibly cause his rank to be lower and not get a scholarship.

So, if the kid is honestly in THAT category.. I guess the choice to push him to work would be more difficult.. knowing it might hurt his chances.

But, if he is just run of the mill and sports aren't his ticket to a scholarship... maybe he should be asked to work.. even if it might be just for the summer to save some money to cover some expenses throughout the year for insu and gas.?

I have 3 step children. Ages; 21, 18 & 15.

The 21 had his first job at 16, got straight A's, and bought his own car (we matched what $$ he put in).

The 18 is now a senior in high school, struggles to pass and admits that he cheats when he can, doesn't have a job or a car.  He father (my husband) & his BM have not forced him to get a job.

So, I am the only one who sees anything wrong with this. My husband and I have gotten into so many arguments over it....

HELP!!!!!