This is a difficult one.
You don’t like them very much would probably cause friction on a holiday, I think you and your DP would be more upset if they holidayed with his sister and her family and left yours out completely??… you’d probably be on here asking ‘I know they don’t like me but they should’ve invited my DP & DC?!
It’s tough not being considered but maybe they just think you’ll enjoy the break too (time without DC).
Also look at it the other way round… if your DP didn’t like your parents, would you just never see them? Or would you take the children and visit without him? I wouldn’t give up seeing my parents or spending time with them for my partner however much he/she meant to me.. I love my parents too and want my DC to have a relationship with them.
Have you spoken to your DP about it all? What’s his views?
now the kids are through the baby stage could you make efforts to rebuild relations with his family? I know it’s tough when people are overbearing with opinions on how to raise children but that’s down to your DP to state that they need to back off.
My family doesn’t get on with my siblings partners. It’s such a difficult one because if my parents invited my brother and his DC on a holiday but also invited his wife, not only would she ruin the holiday but I wouldn’t go because I don’t want to be anywhere near the woman!… (but there’s a lot of trauma involved in my situation!)…. Have you actually ever had an argument with them or did you just go low contact with no explanation?
Im also a little concerned that this is a lie… I’m not sure anyone can book a caravan ‘last minute’ during the 6 weeks holidays.. I mean most places are booked up months in advance.. so have they booked it months ago and kept it quiet? Did DP know about it or have they just invited him last minute so that you couldn’t get time off?
Whatever the situation though, your best bet is to enjoy your days off and arrange to go out with friends, book a spa day, get your hair and nails done or whatever… but just give yourself a pleasant weekend on the days you’re not working! Be sure to tell DP that since they’re all having a holiday you’ll be treating yourself too! He’ll tell his mum that you are making the most of the break - so if she is doing this to be mean to you then she’ll know it’s backfired and actually think she’s done you a favour! However I’m sure they’ve just booked a holiday and wanted to spend time with the grandchildren!
Maybe it was innocent and they booked and when they mentioned to your DP he just said ‘@Isthisrea is working so will just be me and the kids’ (maybe this was the only weekend available for months).
But I holiday every summer with just me and DC, my DH used to come too but he was difficult, so I started booking without him. Nothing worse than going away with someone who doesn't fully want to be there!