Was I in the wrong to post this?

Quite.

Was I wrong to say this, or has my SIL taken it to heart when it wasn't meant that way?

A bit of both I’d say OP.
But at least your SIL had the grace to message you privately rather than for the world to see.

I think the onus is on you to respond now.
Try responding positively to that private message. Invite her for a coffee and talk about it. You could say you are sorry you hurt her feelings with that fb post as you really hadn’t intended to and in retrospect you can see it hurt her feelings. And maybe if you both put your minds to it, you can find a way for you to have more time with her dc.
Use this as a way to improve your relationship rather than digging your heels in.

Good luck, OP, you have a lot negative feelings swimming around and it must be so hard for you.

Your SIL needs to give her head a wobble and learn to read.

Your meaning was clear. I have the same sense of guilt as my mom’s only daughter. I think the experience of your daughter having children is very different to when your son does and feeling guilt at not giving them that experience is normal.

I hate people who read things with emotion!

My be thoughts exactly!

Your SIL needs to give her head a wobble and learn to read.
Your meaning was clear. I have the same sense of guilt as my mom’s only daughter. I think the experience of your daughter having children is very different to when your son does and feeling guilt at not giving them that experience is normal.
I hate people who read things with emotion!

Hard disagree. That's like saying your children would be more as important as grandchildren that a brother's children. I think you need a head wobble.

Also it’s absolutely fine to use your social media to discuss your issues with social media. A friend of mine has done this and honestly it has been so informative (she talks about it openly to remove stigma around infertility which she says is especially pronounced in her community.)

Just to expand on my previous comment, SIL didn't come to the wedding as she said she didn't want to leave her baby (8 months old at the time), and that she didn't want to go somewhere he wasn't welcome.

Good Lord your SIL sounds like a tw@t.

This seems like a massive assumption on your part.

Your updates suggest this is the final straw for SIL and she’s had enough of your attitude to her family. More than fair enough I think. Infertility is shit but it’s not and shouldn’t be carte blanche to behave in a selfish inconsiderate way for years on end.

Your nephew is 4, he was excluded from your wedding 4 years ago because of your fertility issues which must have been present for some time by then and your fb post sounds like something someone might post in a fog of new pain and shock, not an ongoing issue of several/many years.

You're still excluding your nephew by prioritising a dog over a child that’s related to your husband, please don’t try to claim you adore him. That’s insulting everyone’s intelligence. And you don’t have to adore him but you’re very wrong to try and interfere with his relationship with his grandparents by never leaving the dog at home.

Having been on both sides of this I'm sorry but YABU.

Your Facebook your words absolutely, but your phrasing completely ignored the grandchildren that exist and that is unfair. Your SIL not attending your wedding as she had a small baby is totally understandable and I'm surprised you wouldn't make an allowance for her.

As for a fear of dogs, most phobias don't have an age limit so your nephew being four really makes no difference at all.

Infertility is an absolute hell hole and I am sorry you're struggling

I’m sorry you chose to read it that way.

Do you think your might be projecting your experiences?
I think the SIL’s use of language is OTT but the OP didn’t want her baby at the wedding and yet appears annoyed that this sister didn’t go and that it’s somehow related to her bringing her dog everywhere.

It’s also really weird for your SIL to be the one to message you about it and not your actual sibling.

I would just have seen zoned her and deleted the message without response.

Never leaving your dog at home must be massively irritating to people. Do you take it to cafés and restaurants, too? Can't be healthy for the animal to go everywhere with you.

Definitely not. No.

And makes no sense in the context given that the OP included her in-laws in her post.

You just seem very emotional which is fair enough as you are struggling yourself. But encouraging the OP to be dismissive of her SIL doesn’t seem constructive.

The SIL is a twat for not wanting to leave her tiny baby, but the OP is NOT a twat for not wanting to leave her checks notes dog? Okayyyyyyyy.

I am “struggling” - news to me.

I think the one emotionally reading is the one having an emotional response to a fairly non-controversial comment.

That would be you FTR.

There is nothing to be gained from OP responding to her SILs emotional reading of her status. When people engage in that manner the best solution is to ignore them.

No.

Only the bit in bold.

I meant struggling with infertility.

When I was going through series of miscarriages, I didn't post about it on FB. I didn't dismiss children from any events I hosted, and I certainly didn't try and make anyone feel they couldn't talk to me about their babies. In fact, I spent a week in Finland helping out with my BIL and SIL when they had a newborn. Did it hurt? Of course it did. Every time I held the baby or smelled his little head I nearly cried. But I would never have behaved like this.

My pain was just that - mine. I'm not infertile so I can't speak to that, but at that point I worried I was. It's not an agony I wanted to spread about.

The dog thing is just silly. I've got two dogs, four cats, a rabbit, two guinea pigs, a rat, and four horses. They're lovely but they're animals. If any family member, especially a child, was afraid of them, I'd ensure they didn't have to deal with their presence. The fact OP can't see how hypocritical she's being about not leaving her dog at home when she expected her SIL to leave her baby at home for her wedding is just absurd. It'a a fucking dog.

Which is news to me.

I will say as astoundingly generous it was of you to do that I wouldn’t expect the OP to put herself in potentially upsetting situations like minding little babies.

So when you said “you have the same sense as guilt as your mum’s only daughter” you meant?