@Starlightbright200
I think you are both reasonable and unreasonable.
I can understand why you wanted some cover for delivery- not unreasonable, given you have said you had a very quick Labour and the wider family are far away. I understand it would be nice to have more support- but this is what happens if you don’t have family close by or parents who are in poor health. It’s not ideal, but you made a choice to have children and to live where you do. I would also say you knew what level of support is available to you when you decided to have another baby, and presumably decided the status quo was something you were comfortable with when you decided to have a 3rd child.
Your FIL does not sound an overly involved grandparent, which is not what you’d hoped for and I understand that is disappointing (particularly for your partner). But, he also still works- ? Full time- and lives far away from you. He probably can’t actually be there as much as you would like, even if he wanted to. On the plus side, you say he is good with the children when you do see him. If you don’t value what support he is prepared/able to give, and feel he does not make enough effort- then simply scale back the effort you make with him accordingly. It does not have to be a big drama or a big falling out.
I do think, though, that I think you have very seriously taken advantage of your mum if she is so exhausted after 2 and a bit weeks (2 weeks before the birth and baby now a few days old) that you needed to try and draft in help to give her a break. I think you should reflect on that aspect of you and your partner’s behaviour during the last few weeks and how you got to this point. After all, you said she was there to provide cover just in case you needed to make a quick dash to the hospital- she was not there to run around after you all, doing your housework (possibly also helping with meals and childcare).
What were you and your partner doing in the last 2 weeks? I get you were heavily pregnant, but what would you have done if your mum wasn’t there? You’d both have had to crack on with it. I’m not saying she would not want to help at all, of course she would- but why did you let her do things to the point where she is so exhausted you felt the need to get FIL over to give her respite? You could, and should, have insisted she pace herself. And now that she is needing a break, you should let her get one (without needing to wait until you have someone else to help). Why does she need to come back after a rest? Why can’t you and your partner cope by yourselves?
I don’t mean to sound rude, but I do wonder if this sort of expectation/tendency towards taking advantage of others has perhaps impacted on the level of support available to you?
As for your FIL, he did have pre-arranged plans and he did not wish to drop them. I don’t think it is unreasonable, especially as you wanted help so your mum could have a break- it wasn’t like you haven’t had any help/ support at all and were both at the end of your tether. I think most people would think “why do they need almost consistent help when they are both at home and her mother has been with them for weeks?”.
You are recovering from birth, but your partner isn’t- why can he not manage to do the essentials with your support as you are able? How long are you expecting to have 24/7 on-site additional support from your mum or someone else? It just seems a bit, I don’t know- precious? we managed perfectly ok between us after the delivery of each of our children- it was exhausting, chaotic etc, and yes the house was not spotless, food was either quick and easy or things I had prepared and frozen in advance etc. But it was fine! You would be fine too, I should think.
The fact your FIL felt the need to say “I don’t want to fall out with you” makes me wonder if he then did not contact you because he thought didn’t want to hear from him. Perhaps a little childish- but your partner did not call him either. I suppose it’s also possible that as his wife had been in contact, both your partner and/or your FIL didn’t feel it was necessary. Or perhaps he felt you would not welcome too many calls and as his wife had already been in contact, it would be annoying if he called too (though a message asking if it was ok would have sorted it all out, if that has been the case). The fact that your FIL didn’t immediately offer another date is not shocking- I can easily see why he might not —perhaps he thought you only wanted help that particular weekend and so offering another date wasn’t necessary/helpful.
You then phoned to “have it out with him”- I think that was for your partner to do, in all honesty, if he is unhappy about the situation.