Please try and imagine the scenario:
You and your OH are going through a rocky patch and decide to call time on the relationship. He moves out and not long after, tries to seduce another woman by buying her a rather expensive gift. She refuses it saying it is innapropriate as they hardly know each other. He's stuck with it.
He doesn't know that you know this!!
A couple of months down the line you both talk and agree to give thing another go, albiet slowly and remaining living seperately. You then find out he his planning to give you the gift he bought for the other woman for your birthday and as he doesn't realise you know - he expects you to be over the moon with it!
So how would you handle this?? Tell him before hand not to give you anything that was orginally bought for someone else and hope he twigs on?? Tell him when he gives you it that you're a little offended he gave you something that another woman didn't want?? Or just accept the gift and say nothing??