Hi all, my first post here after reading a lot, very useful information here including what I found about 'disengagement' which I'm mulling over.

I'll try to be brief while also sharing the major points. Clearly I arrived here for a reason.

Basis:
I am in love with a great woman, she's a single Mom, raised her two 16yo twin girls without the bf in their life whatsoever. I knew this girl 20 years ago and now we are engaged, living together, aiming to be a 4-person family, I aim to be as much of a parental role as I can while knowing I am not 'the' father, and at over a year together much progress has been made, and also many walls have been hit.

Challenges:
What drove me here for advice is that recently after me trying for at least 6 months to point out that one stepdaughter is highly likely as a case of ADHD (and I would know/see it) and I don't mean light, my fiancé (the mom) has only this week FINALLY admitted that some of the things we've been observing in the one daughter, and behaviours that have been causing us grief and arguments for months, may need a deeper look. She has been in denial, as she does with MANY MANY other things. I am trying my best to be a good guy, contribute where I should, be polite and quiet where I should be, and basically trying to build a relationship with this woman and the girls.

As we try to deal with discussions about things like this serious ADHD topic, or even less serious things like chores, she defends the girls all the time, concedes points to me only after very long arguments, and most importantly, often does not appear to be on my side, or want me on hers. Since we got engaged and before, I've always said "as long as we work through things together, I believe we will do well together. When she's defending, closed, stubborn and difficult, it doesn't feel we're on the same team at all.

To share some examples of what I mean, consider the following, and the side-effect of these situations is that I feel myself gradually withdrawing or at least not wanting to invest the time and effort into looking out for the girls. I do care for their long term welfare, and yet keep getting bitten by Mom who says she respects my opinions, but constantly disrespects them, defends against me, and argues about things.

Situations/examples:
- her girls have atrocious table manners, eg, they are 16 and a list of manners 6yo's should know is even more than they're doing
- when I originally brought up the table manners as delicately as I could with just the mom, we had huge arguments, and only after months did she finally start trying to get the girls to improve their manners
- the floor was not mopped well, as a result of the one child not putting any effort into it. Mom's response: maybe she doesn't have the strength to mop well (she's a 16 year old 5'9" girl). Her second response was "maybe the mop isn't good"
- dirty toilet after being "cleaned" by the daughter - we're talking untouched toilet seat, so not clean at all - response: if we had a white seat it would be easier to see it's dirty (it was obvious)
- even something as simple as locking the condo door (I live in a ground-floor condo), she argued not saying "i'll try" but rather rationalizing that she can't lock it because she's not used to doing that. This went on for months, literally, arguing about locking an external door.
- lights - I am the only one who turns off lights in our condo. I am a bit green-minded, not crazy that way but at least turn off lights when not in use. She defends her girls and her saying "in our last condo we didn't have to pay for electricity so we never shut lights off". We don't pay here either, but the point is lost clearly.
- while doing a screening test for parents to fill out, about their kids potentially having ADHD, which I got from my own doctor to try to help US assess her daughter's situation, mom decided she didn't want to give high scores on any attributes regardless of the question. Part way through the survey she got upset because clearly her daughter was getting flying colours for ADHD flags. She got upset, and finally accused me saying "you just want her to show up as having autism", which is obviously a) denial, and b) insulting and hurtful.

Needless to say, to summarize into one single issue, she is very defensive as a Mom, it creates a rift between us constantly when all I'm trying to do is my best at being an involved step-parent and team-mate for the mother. I wish she'd give me more of a feeling we were in it together, but I get more that we are adversaries. I am a single guy with no kids trying to be a valuable member of the 4 of us, and it doesn't seem she realizes even in the least that there's some obligations she has to meet me half way.

I am becoming more than just a bit concerned, and when I read here and realize that 'disengaging' sounds like a good way for me to stop getting upset, upsetting her, and that I might be better stepping back on the parenting. That said, if I do that I will feel I'm disengaging from the entire relationship, because since the beginning my hopes were to do my best with all 3 of them, not just the mother.

Extra details: The girls are nice, and while they are typical teens, they're pretty good for teens, which I know and realize all the time. I often say that it's not the girls that are the challenge, it's their mother, and I do believe this is the case.

The more I read and find, the more it seems that if changes aren't taking place now, they won't later. I also see that if the girls are raised a certain way up until now, age 16 isn't when to try to change things.

Anyways, sometimes things are GREAT, and other times I feel like the odd man out, and that I am not wanted in the parenting role, and that my contributions and wants are realized. I honestly don't know if marriage makes sense and while it breaks my heart to think of going any other way, I know here there is a lot of experience and so I ask for advice from the group.

Thank you!