Third Party Keyholder?

Has anyone had any experience with a third party keyholder outside of your marriage/relationship? My wife and I have polar opposite sex drives. I like all things kinky and she has no desire in much of anything. She feels she cannot please my desires and has asked if I’d be open to a third party keyholder/dom instead of asking me to change. She also asked if I’ve heard of such situations. I feel like I’ve read something on here before about such arrangements but my biggest concern is our marriage with mixing in a third party to please sexual desires and fantasies. We’ve discussed our concerns and such and are both open to it. Curious what other’s experiences with such have been like and how it has affected your relationship. Thanks for any feed back!

Ps. The third party would be a female

 

We both like chastity for how it changes my attentiveness in our relationship but the downside is the sexual desires that come with it. When I’m locked, I like to be feminized and want to be controlled and submissive. My wife does not have any desire to be in control. We are still early in this discussion but I think it would be more of someone who is comfortable fulfilling my sexual desires and fantasies. In the most blunt way, I would say I have the sexual drive of a high schooler while she has none, which poses concern for the healthiness of our relationship. Btw, we have been together for 9 years and have been married for 1 of those years. Of course communication will be the most important aspect of all with something like this, which I do not believe to be a problem.