Is it safe to have sex with a condom AND spermicide?

Lube and spermicide are two different things.

Spermicide is to kill sperm so it cannot fertilize an egg. When using spermicide avoid nonoxynol-9. The short of it is that it can cause irritation making the risk of HIV higher. Read this: http://www.goaskalice.columbia.edu/1784.html

Lube is to make things go more smoothly especially if there are dryness issues on the part of the woman. The thing you've probably heard is that some lube can break a latex condom. Latex is highly effective, but it can be temperamental. It is sensitive to heat (so no back pockets or wallets or glove compartments!), it is affected by friction (so NO doubling up - two don't make you safer), and latex does not like oil! This is the part that you might be thinking of. NEVER EVER use anything for lubricant that was not made specifically for use with a latex condom. Any oil - cooking, massage, perfume - will cause it break. Anything containing oil can also cause the latex to break. Anything means lotions, lip balms, conditioners, etc. Read the ingredients of any lube. Make sure it is water-based or skip it.