My wife and I are both bisexual and we have a bisexual couple we spend time with 1-2 times a month. My wife is totally onboard with me having sex with another man and participates.
When we were first together (our mid 30s) during a post sex "sexual past" pillow talk in confessed that I had a couple suck buddies back in HS/college. One was a regular. Thought she would flip out but found it interesting. Watched a few gay porno vids and it always got us ramped up. Evolved into her playing with my ass with a plug, one of her dildos and eventually pegging me with a newly purchased strap on. Before one such pegging she had me on my knees sucking on her strap on. She looked down at me and said "so that's what you look like with a cock in your mouth"! Well, we continued pegging and my getting her ass many times. A couple times while pegging me she'd say "I'll bet you're thinking of a real cock, aren't you?" That morphed into having several MFMs with the same very straight friend. After one such MFM she thought it would be hot to hook up with a safe bi guy for some MMF fun. Things were definitely looking up. We looked for months with no luck, while still continuing or MFMs. Then one day......BANG!.....EVERYTHING stopped. Her decision. Something a proper wife and mother shouldn't be doing. Unfortunately for me, those awakened desires didn't go away. The bi side really reared its ugly head when my wife introduced me to her gay hairdresser. Masculine, tall, nice looking........he later told my wife that he thought I was hot! Why she shared that with me I'll never know. Since in our house SEX is now a four letter word, was she trying to push me to her friend? A nice guy I am now fantasizing about more and more. We started texting/sexting and I could see myself getting in to him, and him inside of me. He is a total top, which was fine with me. I went to his shop a couple of times for a "gay" haircut (wife said I did actually look the part), and after the last one had a brief makeout session in his office. He made the advance and afterwards said he just wanted to make sure I was into him. He saw my bulge and shortness of breath so he knew I was. Then BANG again. Wife tells me he's selling his shop and moving out of state with an old BF. Well SHIT! So, to answer the OP question, she knows of my past, I'm sure she knows about my desires and fantasies (they just don't go away), but doesn't want to acknowledge or participate in ANY sexual activities.