Hidden twin?

Kaleigh
I know this is ridiculous, but humor me, please 😜. 
I'm 12 weeks 1 day today. I got pregnant while taking clomid. My husband was CONVINCED we were having twins. I had my first ultrasound 3 1/2 weeks ago when I was 8 weeks, where they confirmed only one baby. I thought that would be the end of hearing from my husband about twins (don't get me wrong, I'd love to have twins). He's still somehow convinced I'm pregnant with twins and they just "missed" it. 
I'm just curious, has that happened to anyone here or anyone you know? I'm just wondering if it's even possible?Â