Infertility, Secondary Support Group
"Secondary infertility" is difficulty conceiving after already having conceived and carried a normal pregnancy. Apart from various medical conditions (e.g. hormonal), this may come as a result of age and stress felt to provide a sibling for their first child.
Your sister in-laws should understand that while you are happy for them, you have to protect yourself as well. I would ask both of them to talk about other things besides pregnancy.
How long have you guys been trying?
~Sara
I know how you feel. When I hear that other people are pregnant I really want to be happy for them, but they are so hard to be around. I try to find excuses to miss the baby showers especially. It can be very awkward because people know that it's hard for you (not that they could ever, ever know how hard) and so they leave you out which is also hard and hurtful. I would try to avoid being with the two of them together as much as possible or if that's not possible ask them nicely to have their pregnancy talk when you're not around. It may be awkard to say, but it will be worth it in the long run. Hang in there. Your time is coming!!!
My close girlfriends in my mom's group are aware of my pain. I try to tell them I am having a tough time right now hearing so much talk about babies and pregnancies. They seem to understand for a very brief moment, then a few minutes later another mom goes back to talking about the very thing that I said caused me pain.