Is it advisable to do intercourse daily? My husband says that daily intercourse will make him weak and lessens the amount of sperm coming out...

Really depends on your eventual aim.
If you are Trying to conceive it is better every other day, but go with what every suit YOU BOTH.

I think he's giving you a lame excuse...

Never made me weak doing it every day... and I'm 50. However it does somewhat lessen the amount every day (sperm count not time)... but this only matters if specifically trying to get pregnant and you are keeping a basal temprature chart and trying to maximise chances on specific dates and times because you are having difficulty.

Depends on his age about being week, it will lesson sperm count if you are trying to get pregnant.