You can always take one of the boys that your husband separated from his parents and give him some motherly love in front of your son 

Secretly take a picture of your husband's tiny penis and post it here.

Unfortunately science has not yet developed a camera capable of seeing objects that small.

You could invite men and boys your husband and son hate over to your house (while they're still there) maybe wear some skimpy clothes while they're over, outright flirt with them but deny when accused by your hubby.

Alternatively, film yourself fucking them, upload it online and wait for them to find it.