Rene Herse says that conventional rim/tire width standards are not carved in stone.
https://www.renehersecycles.com/myth...eed-wide-rims/
I think I can go to 55mm on 19mm internal width rims. You didn't mention how wide your rims are, but I am guessing 45mm tires will be fine for you, as long as you clear the chain stays. Decrease your tire pressure to something reasonable and comfortable.