XDrinks all of the coffee - Will, he is often grumpy before his first cup of coffee. Matthew often goes for a jog in the morning to wake up instead.
Brings up adopting a pet - Will, he doesn’t so much bring it up as he brings home a new rescue and tells Matthew they got a new dog.
Kills the bugs - Matthew, Will is used to living in the country. Bugs are part of life there so he doesn’t mind them as much.
Cooks the meals - Most of the time it’s Matthew, he cares about what he eats and makes great meals for the both of them. But sometimes Will makes a great seafood gumbo or bakes the fish he brings home.
Starts getting into holidays way before they should - Matthew, Will would let the holidays pass without really noticing, but Matthew is already buying holiday decorations a month before because he wants to celebrate everything with Will.
Initiates the couple selfies - Matthew, he is so proud to be dating Will, he wants all their memories in pictures.
Forgets the birthdays and anniversaries - Will, but Matthew doesn’t mind. Will also learns to cover it, buying gifts when he sees something that he thinks Matthew would like and keeping it hidden until Matthew wishes him a happy anniversary so it looks like he doesn’t forget.
Always ends up with too much junk food after grocery shopping - Normally neither, but sometimes Matthew splurges.
Nicknames the other - Will, I always imagined he would give awful nicknames like he did in the book, calling Matthew things like Hotlips or just Matt.