Apple Watch connection to 2 iPhones

You can do it.... but for each change the watch must be erased before pairing again to the other iPhone.

As others have said, one phone can support several watches so you just select the one you are wearing, but one watch can only be paired to a single iPhone at any moment.

You can have two Watches on one iPhone but not one Watch on 2 phones I believe.

That's also my understanding.