You have to get the cost per trip down. I recomend you go sailing more often. If you go sailing 50 times instead of 25 times per season you cut your costs per trip in half.
We don't know enough about your finances, and your family to be able to offer concrete advice. It sounds like you're already considering cutting costs. That is where I would start.
I will however offer an anecdote. Buying my sailboat is the one and only significant financial decision that my wife and I have disagreed on during our 23 years together. I went ahead and bought the boat and am glad I did. We've had the boat for 11 years now and while she is not an avid sailor will join me on occaision. I keep telling her it's the only thing that keeps me sane, especially after I've had a particularly stressful stretch at work. She now appreciates how much enjoyment I've gotten out of the boat. We've had great family sailing weekends, that the kids who are now in college will always remember. For me, it was the right decision, only you can answer the question on how much you should spend on your sailiing habit.