Hi!! It sound like your wife, and yourself, DO have the potential of taking your sexlife up to the next level, but I can also understand her nervousness and retiscense, too. Many years ago, I used to place ads, offering my services as a photographer/videographer and was invited into many couples' bedroom to help create some "memories" for them. It was a great way for them both to relax, with me filming discreetly in the background. It would come to a point where most inhibitions would fade away, and I would ALSO be asked if I would like to join in........which I never refused, of course!! All I can say was "Thank god for the tripod"!! Maybe YOU might consider going down this road, with the understanding that the "third party" will only join in if both of you were comfortable to do so. If not, you would still have some great, intimate memories.....and, maybe, feel more confident the next time the opportunity came round?
Hope this helps. Feel free to message me if I can offer more
xx