Re.:
I am 57 and her 45. We have been together since she was 28 when I could use her hard. Now I struggle to gain an erection and only get turned on by the thought of other men fucking her. Am I a cuck?
I'll respond to your comments and question in reverse order, since
appears to be the reason you've posted on this forum. Briefly, the answer is no. The definition is: "cuckold — a man with an unfaithful wife." It's short, simple and straightforward. If your wife has not taken a lover (or lovers)... and has not done so in the past... you are not a cuckold, regardless of whether you have a secret or openly-expressed desire for her to do so.
It isn't unusual for a man in his mid-50's to find he can no longer get it up easily for his wife — i.e., to find he has erectile dysfunction (E.D.). This is especially likely to be the case if a man has long-term, or even not-so-long-term, diabetes. (There are other potential medical reasons.) Also... although I'm not an M.D. ... my impression is, E.D. can be related to decreased testosterone production as a man ages.
E.D. is basically a hydraulic problem, so the most straightforward solution would be to see your medical doctor, tell her about your problem in a straightforward way (there's no reason to be embarrassed about it), and ask her is she thinks a Viagra prescription would solve it. Be aware that different dose levels cost the same, so you'll be best off to ask for the highest dose they sell, then... if you need less... cut the pills in half or thirds, thus reducing your effective cost by a factor of 2 or 3. Also, there are equivalent brands like Cialis, etc.
Regarding your subject line: women produce testosterone, although in smaller quantities than men, and as women age into their thirties and forties, their testosterone production increases, while male testosterone production decreases in middle age. This may be accounting for your observation that your wife is becoming more dominant (although you haven't provided any details). This phenomenon may also be related to the (often secret) desire many men apparently develop to become submissive husbands who are dominated by their wives.
If you feel you are moving in this direction, and your increasingly-dominant wife might welcome this change in your marital roles, you might consider ordering and reading:
Sutton, Elise, 2003, Female Domination: An exploration of the male desire for loving female authority (298 pp., softcover)
(available from well-known online distributors), and/or see Ms. Elise's website (google Elise Sutton).
You might also consider reading the site "Real Women Don't Do Housework," in which the author, Lady Misato, suggests a somewhat more psychological approach to interested women.
Returning to your question: if you're beginning to feel... or perhaps have long felt... desires to transition to a "cuckold husband / hotwife" form of marriage, I suggest it will probably work out better and more smoothly if your wife first takes some time to become the dominant partner in your marriage — in effect, the head of your household — to the point that she is acknowledged as such by both of you. The two of you can then implement a strategy for her to take lovers in a way that will maintain, and possibly enhance, the quality of your marriage (rather than destroying it).
Thanks for posting your wife's photo, BTW. She looks attractive. My guess would be, she would benefit from taking control of her marriage to you (per the above), and expanding her sexual horizons.