Finding Our Boundaries

My wife Amy came home from a night out with her girlfriends and immediately confessed she'd had sex with another man.
Apparently he'd chatted her up in a bar, then they went to his car where they'd had sex.
From what my wife initially told me, she'd sucked his large cock, then he'd fucked her doggy style on the back seat.
That's when I asked her for more details. It took some coaxing to get Amy to reveal all, but eventually my wife went into detail about the guy himself. How he looked, his height, muscular build, his chat up conversation and then with a bit more urging my wife told me about his cock, how big and how thick it was. That is was uncircumcised and about eight inches.
I made her tell me just how she sucked his dick and how he fingered her pussy as she gagged deep throating him. And as she began to describe how he entered her from behind, she stopped her confession to tell me I'd gotten a hard on in my boxers.
My wife was correct, I'd become incredibly turned on listening to her account of being fucked, and any notion of getting angry had totally gone.
When she carried on at my insistence, she leaned forward and took out my six inch dick. Stroking it as I encouraged her to tell me how his cock felt fucking her, Amy let me know every detail of how he fucked her and how he'd made her orgasm twice before he'd cum deep inside her.
That last comment about her receiving his seed made me push her down so she was sucking my cock. But I wanted something else, something I never knew I'd get so sexually excited about.
Turning us around as Amy sucked my dick, I began tonguing my wifes pussy, knowing I was also licking out the guys cum from her c**t.
It was such an amazing ten minutes or so as my wife orgasmed on my face, then my cock exploded in her mouth.
That night as we fell asleep together, I made up my mind, I was going to enjoy the experience again.
Waking up with a woody, I entered my wife spooning her. As she woke up I told Amy I wanted her to fuck other men and said it in such a way, she fully understood I meant it.
It's now been eight months since her first time cheating on me. Amy has in that time had sex with five different men, but recently slowed down when she met Craig.
He's in his late thirties and he's the first I've witnessed fucking my wife.
It's abundantly clear he enjoys fucking my wife, but he's also begun to try and involve me. He's openly bisexual and as he often says "I enjoy receiving blow jobs from, and fucking both sexes".
Amy is extremely active when Craig is at our home, often having him fuck her multiple times. But she's also started to encourage me to suck Craig's cock.
I haven't done so, so far, but I have licked out his cum from my wifes pussy and arsehole. I like the way his cum tastes, but I'm not sure I'm ready to suck cock yet, but we'll see.