You should tell your boyfriend about your feelings for your ex.
But before doing that make sure your ex feels the same way. But if
your ex does not then just try to get over him.
'Ex' means the relationship is over and unfortunately, that
means that you ex boyfriend and ex best friend can date whomever
they want no matter how much it hurts you.
If you still think of your ex-boyfriend and talk about him that
means you ain't over him. If you continue to hate your ex that
means you still got feeling there.
'Ex' means the relationship is over so there is no reason you
should be in his life or even discussing that your ex boyfriend
adopts a child. If he is with someone else and you are just friends
then it is up to your ex boyfriend and his mate to decide whether
to adopt a child or not.
obviously you aren't over him, but he is most definitely over
you. you weren't the one he wants to spend the rest of his life
with. deal with it and move on.