Enjoy Watching Him

The first time we had a threesome, it was on holiday in Spain and the guy was more interested in my husband.
Bizarrely it turned me on so much, as the men sucked each others cocks.
When my husband was fucking me missionary, our guest got up behind my husband and slid his cock deep inside my husband's arse.
It was an incredibly horny experience and one I think my husband enjoyed too.

Around six months ago, we had another threesome, but there was hardly any contact between my husband and the other younger man. But my husband did lick and suck his cock clean after he'd fucked my pussy and arse.
I spoke to my husband afterwards, explaining how I'd have loved to watch him taking cock up his arsehole again, just as he had on our holiday in Spain.
He got a little embarrassed, but I knew it turned him on, us talking about him taking cock, as we fucked again in the shower.

In a few weeks from now, one of my ex colleagues is going to be staying a couple of days as he attends a business conference. I know for sure my older gay ex colleague likes my husband in a sexual way. So how can I explain to my husband, I'd get just as much enjoyment out of seeing him being fucked, as he would taking cock.