DH is 40 this year

[digusted]

He has had a 4 day weekend in spain with the boys and now wants a huge party. For my birthday he has invited his mother to stay we don't get on. I don't want to arrange a party at home for him am i being unreasonable

Nope. Definitely not. How many times over does he want to celebrate his birthday anyway?

Of course, you could arrange a big party on YOUR birthday, thereby diluting the effect of your MIL's presence?

Go away on your birthday too, leave him there with his mum...