The specifics of this are incredibly outing so changing a few of the details (hopefully it still makes sense! Please bear with me):
My friend has a boat she can no longer afford. I am interested in her boat, but not 100% sure I need one at this time. We had an agreement before lockdown that I would have 100% ownership of the boat for a trial period of 2 months (all of April and May). I would pay costs totalling 350£ a month for this period. In exchange I would have 100% use of the boat and my friend would not use it at all. Because of lockdown I am not able to use the boat, but I agreed to pay before this and a deal is a deal/I value my friendship so have paid for April and planned to pay for May. However my friend has mentioned several times that she has been using the boat during April.
DH thinks I would be crazy to pay for May as agreed since I have not used it and actually friend is using it which breaks our agreement/essentially means I am paying for her to use her own boat.
I am in two minds as I value her a friend and don’t want to be petty, and lockdown is not her fault obviously - but equally I’ve paid one month and I am rankled she has been using it.
YABU - pay for May as agreed
YANBU - you paid for one month already and that’s enough/don’t be a mug