Work Mate

Nearly a month ago I got bummed by a colleague of mine.
He's a lot older than me, but his wife is only a few years older.
Basically he wanted a young cock fucking her and after lots of chats at work I visited their home.
One thing lead to another and before long I was balls deep up her pussy.
I'd been fucking her for about ten minutes changing positions, when he began kissing then licking my arsehole. It felt really good so I just let him do it.
Fucking his wife missionary and really getting into it, he got behind me and slid his cock up my bum.
I resisted at first, but he just fucked me deeper and harder. And the more he did, the better it felt.
Soon I was actually backing onto his cock as well as fucking his wife.
When his wife had yet another orgasm, I came in her and he then emptied his balls into me.
It's the best sexual time I've ever had and knew when we were all sat talking together afterwards I'd want to experience it again, especially being bummed.
Well in the past month we have had sex altogether, but I've also just had sex with my colleague.
We've fucked at lunch times when our shifts match and sometimes after work too at his house.
Being honest, I now much prefer having sex with just him. I'll continue to fuck his wife, if they want me to, but I genuinely crave him bumming me.
He has mentioned visiting a cruising place he knows of so he can share my arsehole with other men, but I'm not sure I want that.