DD’s dad’s partner at my child’s autism assessment

she sounds like a devoted step mum who spends a lot of time with DD. I have been through ASD assessments with both of my children and I do think, given her involvement, it does make sense that she is present. she appears to be spending more time work your DD than her dad. I really don't understand the anger.

I’d go with it as it would be useful to have her input. Especially as she might be slightly more objective

Why are you trying to create friction?

she didn’t steal your man, he was never your man.

he is however a bloke who is engaged and involved in the wellbeing of dd, and his wife does a lot of support to ensure your dd has all her needs met.

you’ve got a good co-parenting set up, it works, so don’t be a dick. Maybe your attitude here is what she’s off with you about.

2 heads are better than one, she may suggest questions or answers that your dd dad won’t think of. All of this could help dd.

this woman is not an enemy, be thankful she’s engaged and prepared to pitch in to help her husband and your dd.

You're being totally unreasonable and not putting your daughter first. It's all about you and how you feel

Shift your focus into getting the best support for DD. It's likely New Wife (NW) will have useful insights, will have seen issues which should be noted etc and you should be cooperating with her. Sharing info at handover, explaining what's going on day to day because that's best for DD.

You say your dd is “with her dad” half the week but it sounds like his wife is doing the vast majority of the parenting? If anything it sounds like you and she should be going to the assessment together, not him!

I wouldn't have an issue with her being there. She is already doing a lot of childcare for your child, I'd rather her have the full picture.

You can object unless she has parental responsibility eg court order (maybe married status but check)

I would question yourself why you wouldnt want someone who is 50/50 living with your child involved in their care. I can understand from an ego point of view or if exDP was controlling. What is the worst that can happen?

On the flip side, 3 adults at one appointment is highly unusual. Are there enough seats is a practicality that comes to mind? It is not a circus and your child may feel uncomfortable if potential conflict (and divided loyalties)

I sympathise because I wouldn't like it either but I don't think there's anything you can do about it and trying will just cause arguments and stress.
If she spends a lot of time with dd then she will likely have useful input. They are married so it's not like she is a random girlfriend that hasn't been around long

It sounds like the wife does (the majority?) Of childcare at dad's? In which case she will be very well placed to give info on dd's needs at home and will need to receive the info on what might work going forward. Half of the assessment is talking to the parents so seems like it will be valuable to have her input.