There has been no mention of anullment in the books or in the show up to this point.

There’s no reason that, by using the term anullment, that they are any different from our perception of anullment. The only reason I can think they used it is because it sounds (mind out, sounds) less dickish than divorce, which we more associate with modern ending of marriages.

You’re remembering that incorrectly. He sought Lyanna out because Elia couldn’t have any more children, but he was looking for the third head of the dragon, not invalidating his marriage. It wasn’t a matter of setting aside his children (He believed Aegon was the Prince that was Promised), and he needed a Visenya.

And since I’m here...

Im not positive, but I’m pretty sure that Ned and co. come to the Tower of Joy after the Battle of the Trident, so after Rhaegar’s death.

I’m not the only one laughing at this right? Right?