How much rent should I charge my boyfriend?

I live in iowa, so bills are pretty decent here. This month was a bit under $200 for trash/water/gas/electric in my three bedroom house.

When talking to my boyfriend, who currently lives in a one bedroom apartment (paying $450/mo), said he’s comfortable paying $400/mo to live with me.

If I take the $400 offer I’d spend the rest working on fixing the living room which is literally in the middle of a remodel, but I feel like I’m stealing from him?

Should I feel that way? He doesn’t know how much bills are in my house and he hasn’t asked. Everyone tells me not to tell him and take the 400 and just keep the extra.

I currently have back taxes on the house so I’m definitely going to be paying those off first thing then the remodel after, but idk. I feel weird getting money from him at all, but a girls gotta pay bills.