How do I deal with feeling guilty about my horses' living conditions?

Hello, I understand exactly how you feel, and it is not an easy thought or emotion to wrestle with. If moving them really is not possible, as you say, think instead about what you can do on site to give them the best management you can. Focus on what you can change rather than what you cannot. If the paddocks are small, could you enrich the environment in some way? Add some twigs or branches for them to chew on, from trees that are safe for horses to eat, scatter the food around, and give them the chance to forage. Make the best of the situation. 💕