If I stop training will my muscles turn to fat?
This is a very common and understandable misconception. I think it has arisen through anecdotal evidence of big guys who have stopped training and quickly slipped from being muscular to fat.
If you avoid eating too much when you stop training, what actually happens is that your muscles lose but your body fat stays the same. and that's how you get fatty after leaving workout or any kind of fitness activity.
Instead of leaving physical activity totally you should keep trying to stay active and keep doing some kind of physical activity with a good nutritious and protein enriched diet to maintain your muscle mass.