How to prevent my wide rice noodles from breaking after cooked?
Two reasons I can think the noodle would break apart.


Your noodles are overcooked.
The noodles are sticking.


If you are stir-frying a noodle after cooking, likely I think the first would be the biggest factor. I would typically suggest undercooking the noodle first.


Cook it a minute or two shy of al-dente. It should be soft enough to stir-fry, but still "undercooked".
Drain and then stir-fry with enough oil to prevent sticking.
If the noodles at this point are still not al-dente, you can add some broth/water to the sauce and let it soften some more.