I'm not sure how long is too long but I guess that if there's no damage being done then you can leave them to it. I have a pair that seem to be behaving similar to yours and they've been together for 4 days now.
Hi Jaide and congratulations on the spawn. I've never bred Angels but I found this for you.. http://www.aquaticcommunity.com/breeding/angelfish.php
HTH a little.
Welcome to the forum Lisa :bounce:
Have you looked on the floor for your Betta? They can jump out of the smallest gaps. I keep the water level a bit lower on any tank that has a Betta in it.