"Truth be told, I’ve had trouble
convincing myself that the product is
worthy of the effort needed to make it
succeed. I’ve thought about a pivot and
will probably work towards it, but at the
same time its hard to know if it has the
potential to be worth the effort."
That statement plus your co founder staying home probably didn't help.
Why lack of enthusiasm for current product? Why not build the right product, rather than build the wrong one (and need to fix it later)?