Now if you ever receive coins in that address I can follow up on future utxo movements and maybe figure out some of your activity.. that’s why addresses shouldn’t be shared publicly .. and that’s why Lightning is so much better for that :)

Makes sense, it’s bacon, bacon, bac… you know what though, and hear me out, but what if we think outside the box here? What if we each contribute to a shared account that requires both our private keys to use it? Then let’s keep a shared Google sheet of how much of that total balance each of us owns, and update that record as we transact back and forth until we’re ready to close it. There’d be a few minor details to iron out but that’d be way quicker than waiting for on chain confirmations AND we wouldn’t have to give each other our private keys. 🤯