Apparently I need to be more supportive

I must say, I know quite a few young women who seem to be finding motherhood stressful who then go on to have more children.
Is it societal pressure, do you think?

I think it's the idea of a baby bringing a new start, however unrealistic the idea of it going well might be.

Washerwoman, it sounds like you and your DD are both under a lot of stress. I hope DD feels a bit better after her evening out.

Yes, hopefully it'll do her a power of good.
It sounds as if she has got stuck in a bit of a negative mindset.
Fingers crossed.

I think a few brisk words, along the lines of: 'I gave up my trip to the cinema so that you could have a treat' need saying.
Plus pointing out just how supportive you are being.

The problem seems to be with the partner, working away, flashy car, and a new child sounds like a sticking plaster baby.
That said, her choice; you don't have to put up with her rudeness and ingratitude.
Another heart to heart?

Yes Eazybee I think so.But not wading in ,will pick my moment.Having slept on it thanks for reading a rather long post,but felt better getting it off my chest ! We can never regret our beautiful DGC who is a delight ,and I count myself lucky to see so much of her.Overall DD is grateful for help I know.I have been taken out for lunch and had plenty of thank yous from her.Partner not so much.DH is usually very mild and easy going but has decided to have a quiet stern word with him because tbh it's his thoughtfulness that often causes the stresses.eg.late collecting,dropping her off whilst he 'sorts something at home' only to find he's popped out to buy more designer gear.DH is probably more diplomatic than me,and also his voice will resonate more as he rarely says anything.

Yes a word or two from your OH would hopefully put your SIL on the right track reminding him that if you where available for childcare he would not have the finances for his boys toys,also I would be unavailable sometimes for baby sitting duties and see how they manage it just may change their attitude.
Make sure you enjoy your other DDs company more often she sounds very thoughtful.

I'm glad your DH is on board to have a word. It's really upsetting when everyone involved is trying their best - except for one person.

OMG - he sounds exactly like my DD's partner! Very similar situation. However, childish and thoughtless as he is, we are very fond of him. But I so understand that the constant grumpyness is very wearing! It is difficult, you feel you need to support them, and end up as their sounding board! I often think they would be better off apart, but I hate the thought of a broken family - so I keep on supporting. Our lad isn't mean or anything - just immature and thoughtless. DD had to grow up pretty quickly when our DGD was born, and she seems to have outgrown him. But, like your DD she loves him, so it carry's on. All I can suggest is tread carefully. I normally give my DD a heads up if we feel we have to say something, just to make sure we have her approval.

She needs more external help in the form of nursery or childminding. She is putting a huge load on you not just to care for the children, but be her emotional support too.

She needs to spread that load around, it’s not fair on you.

She is making a poor decision to have another child when she isn’t coping with the one she has.

Muffin the little one does go to nursery when she works,what DD failed to take into consideration or chose to ignore is that her working day is so long with travelling that it's not open when they both leave,and closes before they get home.Hence I do either end of the day,plus overnights when needed due to shifts.The other grandma does the odd pickup ,but prefers to have DGC ferried up to her for play sessions when it suits her,usually her sons only day off which has been an added cause of tension between them.
Yes ditto Knickas63.You're description of our feelings towards SIL mirror ours exactly.We don't dislike the lad,in many ways he's had a tough past -largely ignored by is own mum when she remarried and had another son but now DGC is on the scene guilt tripped into seeing her far more than he has done for years.All very complicated really !But the immature and thoughtless personality has begun to grate recently.It's time he grew up.And boys toys yes indeed.An expensive mountain bike,a brand new tv .games console and apple Mac to name a few despite a bathroom tap that leaks,a drain that keeps blocking and loads of other little things that DH would have seen as a priority. But what can you do?I will counter DD head on if she's rude to me, and leave DH to find a time for a chat about helping those that are helping them.

Parts of this sounds so like my daughter. The only reason I say nothing is we don't live close and I would feel dreadful going home because I love her. but visits are stressful. Be assertive. I would if I lived close. You are entitled to respect.

I know .We do live very close,not our influence but their decision as houses more affordable here than where they lived previously. Plus when our DCS were little we lived pretty close to both my parents and the ILs and our girls had a great relationship with both sets of grandparents,and I think at heart DD wants that too.Sadly she gets little support from her MIL who as DD puts it sees her her as 'just the vessel that carried her grandchild',but then she has little interest in her own son we've come to realise.Very sad.I was extremely lucky to have help without interference-although tbh DH largely sorted ourselves and grandparents provided babysitting occasionally for social things.Not the regular hours essential for working parents,but I think thas so much more the case anyway now. I know deepdown when DD is shirty and snappy that basically it's the relationship with her partner ,and his family, at the root of it.