I have Nick Valentine as a companion now but Dogmeat isn't anywhere to be found! I'm playing on Xbox One so I can't use the console to find him like some people have recommended for PC users. Anyone know how I can find him?
Check the doghouses on your settlements, he might be in one of them, for instance, sanctuary has 3 or 4 of them built already. Also try to return to the gas station, where you found him, he might be there due to some bug or reset.
There aren't many options on the consoles.
Theres is an article about this here.