separating a mated pair

I've had a male and female cockatiel (male now 8 months, female 6 months; we think) for just under 2 months, they were supposedly hand reared however when I picked them up from the seller we weren't allowed in the house and we think they weren't treated the best, and were definitely not hand...

I have a female cockatiel (that I thought was a male), and got a second 'teil (male) to keep him (her) company. They bonded, and have successfully raised beautiful chicks (not my intention). I want no more eggs. When the birds are separated, the male very obnoxious and noisy (he wants to mate...