They do. But not immediately. Usually after the first ooth was laid, sometimes earlier. There are some theories on this topic, as a mated female does not really need another male. So it may be that 1). she attracts males to feed on them and/or 2). she tries to mate with additional males to increase her fitness. Usually point 2). is the one more close to reality, but 1). has some evolutionary implications which cannot be excluded without further studies.
Regards,
Christian