Most money-and-couples advice jumps straight to "open a joint account", as if seeing your shared spending clearly means merging your finances first. Some couples want that, plenty don't (and some can't, for reasons that have nothing to do with trust). What people are usually trying to work out is smaller: who paid for what, and does it roughly even out over the month, not a full financial merger.
This tracker handles that with two named profiles. When you log an expense you tag who it was for, then switch between each person's view and a combined "household" view to see the totals. That two-profile household mode sits in the Premium tier (about $4/month), so it's only fair to say the free version tracks a single person; if you split costs often, Premium is the part that earns its keep. Either way, nothing connects to a bank. Start with the free tracker below, and add the second profile when you want the shared view.