And if there were, hypothetically speaking, it would be very expensive.
Have you imagined that you pay $10-$20, go to Las Vegas with your friends, lose $1000 and the insurance pays you that money back? Gambling insurance, I haven't heard of more stupidity than this in a while. Giving insurance to addicted gamblers is adding up to their bad habit and addiction, you are giving them money to gamble more... guess what, that business would fail in a few days.
I too think the question is rather stupid and is based on the OP having no actuarial knowledge whatsoever.
If there was such insurance it would insure you up to certain limits and paying $10 a month I doubt very much that it would insure you for more than a few dollars loss. Plus the insurance companies would try to somehow investigate your gambling habits. It would not be the same to insure a professional poker player who wins millions every year against a possible bad streak than a degenerate gambler, who would not even be offered a policy.