So a bit of background - I do not get on with my in-laws very well at all. They emigrated 10 years ago, when DH and I were in our late teens, and because he stayed here to be with me it caused a huge rift in the family. Things have got better over the years and MIL has come to stay with us a couple of times, but we still don't particularly see eye to eye.
MIL is planning to come and visit again next year (for the first time in 4 years) and she was talking to DH about when she might aim to schedule the trip. He suggested the later part of the year because we are TTC and he wouldn't want her to miss anything!
I only know this because I was borrowing his phone for something and I "happened to see" the messages on FB Messenger... I know that sounds terrible, but I am not usually the type to snoop at all and I trust him 100%. I can just never resist an occasional peek at his messages with MIL when the opportunity is there, because she has said some horrible things about me in the past and I still feel like she tries to turn him against me. She sometimes says things like "look at your sister's house, don't you wish you'd moved here so you could have had this sort of life too?" (when his younger sister bought a huge house out there last year). I don't know why I do it to be honest because it only pisses me off... I never look for messages from anyone else or snoop further than that - our marriage is generally in excellent health and we love and trust each other fully. I am just very nosey when it comes to conversations between him and his mum, as I don't trust her!
Anyway, in the FB conversation DH also said that he had told his Nan that we were TTC as it had "slipped out" when he went to see her last week (she still lives about an hour away and he visits every few weeks). That too appears to have been in the context of his mum coming over.
I really, really didn't want them to know about it and feel sad and annoyed. I can't exactly say anything because I know I shouldn't have been snooping. I do at least understand why he told his mum, of course he wants her to be there when we (hopefully) have a baby for her to meet. She only comes here every 3-4 years. I just wish he'd talked to me about it first. He probably didn't because he knew I wouldn't like it. Also to be fair I did tell my mum (without asking him first), but that was because we haven't been successful straight away and I know she had difficulty conceiving me. I should have asked him first but there was a natural point in a conversation mum and I were having, and I hadn't planned to talk to her yet.
Anyway, do you think I am being unreasonable? And should I talk to him about it?