I’m assuming you’re not overly close with your in-laws then? I’d personally just tell them how it is and how you feel. I have done it. If it’s their first grandchild then they’re just as excited as you. My family didn’t really make any fuss or bring anything up about the baby. In-laws is was all they wanted to talk about. I tend to be quite stubborn and hardly a push over so they new once I said my piece they stopped going on unless I asked for something/told them something x
My mil said when I was pregnant that she was going to buy all the big stuff and we also moved house when I was pregnant and she was trying to choose our appliances and telling my partner what to buy (choosing models and colours etc) without consulting me. I very quickly told my partner it was too full on and I wasn't okay with it because its not her house or her baby, we compromised on her buying 1 big thing for the baby that we chose (cot) and that was that really.She did also talk of how she'd be babysitting and taking my kid on holiday and stuff without us and I just ignored that because I knew that would definitely not be happening for a long time (she's very impulsive and unpredictable at times).I understood her being excited as it was her 1st grandchild but I could handle that much interference.Best advice I can give is nip it in the bud ASAP!Talk to your partner about it and let him talk to them on behalf of both of you and compromise on how they can be involved without taking away from your experience
Also if they're being this overbearing now I'd be concerned about how much they intend to b involved on the parenting and their input when baby is here. We also had ground rules for when baby was born...nothing crazy just the usual no kissing, no showing up unannounced etc and funnily enough the only person to get a bit funny was mil so I'd perhaps discuss with your partner how you want post partum to look and make sure everyone close to you is aware of that mostly so your in laws don't take it personally. You won't want many visitors straight away, that was honeslty the worst part about having a newborn for us it was just too much having people wanting to come over all the time. I'm due again in September and we've already agreed once close family have met baby once we'll be taking some time to get used to being a family of 4 and adjusting without so many visitors. Remember its your baby and you're in charge!
Ughhh I honestly really feel for you. Mine are exactly like this too and I’m the same as you really private and chill whereas they are so OTT and suffocating. It’s why I’ve still not told them the news as I worry how overbearing she’s going to become & I’m enjoying this bubble of them not knowing right now. What I will say is though, you and your partner need to be a team on this and because it’s his parents so he needs to be the one to set the boundaries so that they see it’s you both feeling this way, not just you as you’ll then get tainted as the bad one. I went through infertility for years so luckily my husband has the same sort of feelings as me, wanting it to just be us 3 in our own bubble, no visitors initially etc but we have both discussed the boundaries we will set with her and I’m gonna let him tell her. My sister in law had a baby 2 years ago, and my MIL made her post partum experience hell. So nip it in the bud now else it might get worse when baby arrives x
Ask your husband to do it in the way he sees fit - shouldn’t fall on you