This should have been something you discussed together before telling anyone. I hope you can sit down now and come to some understanding of why he did it, and what will be the 'rules' from here.

As for surprises, I can really relate. We chose to tell my parents after my first cycle as there was so much I wanted to discuss with my Mum (the female side of things and this was before I found BB). I did grow to regret that for the reason you say - falling pregnant should have been between DH and I, and then I get to surprise the grandparents-to-be with our news. I really missed that aspect, so I stopped discussing things with my Mum and didn't tell her when we were doing any treatment. A few weeks ago I got to surprise them, and it felt as it should be. So there is hope, you may just have to lay down the rules for your parents in law.

Good luck with it all.