Communication questions...Need a little guidance ...

I’m fully aware I’m letting fear of spewing and unpredictable response cause fear in me to sort some things out that are plaguing my mind. I feel like this is also a boundary opportunity, for which I Still don’t fully understand how to implement...
Can anyone offer advice or phrasing on how I “get what I need out of the below scenarios by communicating clearly” and sticking to my needs?

1. This one seems so juvenile to me, but it also seems like an opportunity for H to continue doing what he wants when And how he pleases at my expense.
Up until last month we’ve been splitting the grocery bill down the middle. He decided to spew and say he never eats here anymore (Untrue) and that we shouldn’t be sharing the groceries...then proceeded to tell me to just charge him for the “things I bought for him”. I replied that [i]I can’t read minds and that going forward we can certainly shop separately but that we will be splitting this current bill for the large shop I did.[/i]
He’s used a few things but then I realized the reason he said all of that was because he planned on “not being here” and has been gone for days at a time just popping in to do laundry and bringing in take out food.
I feel like while he hasn’t used as many items as he normally would, I bought everything under the assumption of how we’ve been operating. Do I stick to my guns and charge half? Wait for the blow up and then try to negotiate?

2. I need him to delete an app for security so I can take it over. He will outright refuse and continue to “add me as a secondary user” - I’m tired of having to constantly ask him to add me if the battery dies or when they update the app...especially since he’s hardly been here all month. Should I just literally ask “can you pls delete the app” and not even explain why until he asks?
I’m annoyed that all of these electronic type things are in his control and yet are for my safety right now. He won’t see it this way. I guess all I can do is ask and then go from there?

I’m tired of giving these situations (and many others) so much energy and over thinking ....I try to run ever scenario in my head so I’m prepared and then I’m still not anyway.... argh.