I have a gift for you from my boss. He sent me home early to give it to you and I can't wait for you to open it. Open it! Open it! Open it already! I'm just too excited!... How adorable! He's bought you panties! Pink, lacy, girly panties! They're so cute right? So, obviously that's not all he wanted you to have - he sent me home with a message for you too. He said to make sure you're wearing them when he comes over to fuck me tonight, cuckold. That's right - he called you a cuckold - he especially wanted me to remember to call you that. He said he's going to be the only one who gets to fuck me now so you're going to be wearing panties from now on. He said you can carry on being my boyfriend and providing all the sensitive emotional kinda stuff he can't be bothered with - but you won't be needed in the bedroom anymore - that's for him only now.
I want you to know that I fully support him doing this to you cuckold. The truth is I've been cheating on you with him ever since I started working for him and I just don't 'need' you sexually any more anyway. He's so Alpha and dominant that coming home to fuck you is just unsatisfying. After he fucked me over his desk at lunchtime, we discussed how I should end all sexual contact with you and make this a permanent arrangement. I'll keep myself exclusively available for him, sexually, and I'll keep you in panties. Well it's actually gonna be panties AND a chastity device - my boss doesn't want any 'cheating'. We joked about how making you wear panties all the time would make sure I don't see you as a man anymore - just a kinda sissy cuckold. That's what you are now - a sissy cuckold - a pantied boyfriend who stands by as his girlfriend fucks her real man boss.
So it's panties for you starting right now cuckold. You'd better put them on before he gets here - it's gonna be humiliating enough for you when he turns up to fuck your girlfriend - if he has to punish you for not wearing your emasculation panties too... that'll be super-humiliating. I know you're gonna be jealous - standing aside for a better man to fuck me but you still get to be my boyfriend. You still get to date me, snuggle and hold hands like always - you just don't get to fuck me anymore - that's for him only. I'm exclusive to my boss - and you're exclusively in panties. Pink panties!