I've said this a gazillion times (well, three times):

This is a great excuse to get another bike. It's advisable to have a cheaper, alu bike to ride in wet weather.

If you ride in very wet conditions, especially at reasonable speeds with stacks of road spray, water will find a way to get into your frame.

Sometimes, if I get stuck on my good bike in heavy rain, I roll home slowly (if it's not too far ) to avoid heavy road spray.