It's only awkward if you let it be. I have a very good friend who is an ex because they wanted to move to another continent and I didn't. Foolish in hindsight but whatever. By total circumstance, I'm now dating one of their ex's. That pairing split because of different emotional desires. We all hang out when we're in the same country, hell, the four of us (our shared ex married after moving) are going to the sauna together in a month or so.
It's all very normal as long as you let it be.