The original technique described by Valsalva had little to do with clearing the ears, but I gather that it now also broadly covers closing the mouth and nose and forcing pressure up the tube. I had to do this (several times) for every decent for 40 years, with or without recent infections.
I assume that you have been treated with antibiotics.
If you are not able to equalize with a moderate pressure of this kind after 3 weeks, it does sound a little resistant to clearing up. If all else fails, you might be well served to have a grommet fitted. I have flown with a couple of guys that had a grommet for protracted periods, but this was in the UK.. I am not sure of the danger of infection via this device, but I imagine that swimming would be a problem.