When I first started playing with the band I play in it was just a depping spot. As time went on I was getting more and more playing with them. Funnily enough it was only at practices. The other bass player never missed a gig. Money involved in that, surprise. In the end the band said to other guy that as I had been helping them out so much I would be doing half the gigs.
Surprise, surprise suddenly my playing at practices dried up as he never missed one. I called his bluff and left the band. I went along to see them at a local gig shortly after that and came the question "Has Bill asked you to come back to the band. We never know when Derek is going to turn up".
Sounds a similar situation you find yourself in. Don't pay. If the other guy values his place in the band then he needs to pull his weight.