Big congrats on getting to exclusively BF
Pie used to go up to 10-12 days between poos. We did worry because we had ehard it was usual for older babies, not young babies (this was between 1 - 8 weeks I guess?). But as with Audax's bub, as she got older she got more regular. She did get uncomfortable in the day or two before a poo, and I used to do a little bit of tummy massage as well. Plenty of wet nappies is good, and as long as the poo isn't hard & dry & pellety, then it's probably normal.