Need advice!

My wife and I have been together for 5 years total. Beginning of the relationship, i have asked her during sex and not during sex if she would ever suck another cock in front me of so i can watch. And she said she would do it for me, and if that’s what i want, she would. So i started to try to put it in motion and she seemed to have gotten cold feet wondering why if i love her, why i would want to share her because she doesn’t want share me. So since then, i’ve laid off asking if she’d be down for a third person the past year, but in between introduced a couple bigger dildos and cock extension, and she fucks them like crazy and loves them and squirts all over them. But i can’t get over the fantasy of her sucking another cock, and fucking her to a video of her sucking another cock. Would i be wrong to ask again? Is it wrong of me to continuously want this? I fear that she might take it the wrong way if i ask, but i feel like she really loves the bigger toys? Should i leave it a fantasy? But it’s been 5 years of us together and me trying to see how she felt, and she always said she would at the beginning of our relationship so what’s a healthy way to bring it up again?