Why so unfair?

So I want to start of by saying that I am thankful for everything I have but my husband doesn't agree/want any more kids (we have 2) but part of me still wants more. How is it fair that I personally know friends and relatives who DO NOT EVEN WANT kids but somehow magically and quickly are pregnant! Even one of them thought of abortion because she just didn't want kids. How is this fair?! I am super thankful foe my kids after more than 3 years ttc and dealing with infertility but it's super frustrating when they speak about it and I'm trying to be composed and put together.