IVF...here we come!

I met with my RE last week to basically tell him that we will be doing IVF this summer.  I explained my feelings on "wasting" money on other procedures and told him that I'm ready to move on.  He offered a few other possibilities, but I could tell he agreed.  
Last weekend my husband and I went to dinner with his parents to celebrate my sister-in-law's birthday.  After dinner, I was telling my SIL about our decision.  (She has always been extremely supportive about our IF.  Even when we were both trying at the same time and she became pregnant after 8 months of trying.)  My MIL was sitting there the entire time and did not say a word.  NOTHING!  She showed no interest in the discussion.  No words of encouragement, motherly advice, not a word.  I expressed my concern to my husband on the way home and talked to my SIL about it.  She agreed that it was very weird how my MIL acted.  At first, I was hurt.  After thinking about it, I was angry.
Although I'm sure she didn't want to butt in, she could have said SOMETHING!