What device for my situation?

I am very new to this and I need your help to see if a chastity device would be adequate in my situation and if so, which model would be best.

My partner and I typically have sex once every 7-10 days. I unfortunately have limited self-control and I tend to give in to masturbation at least once, sometimes more between our sessions. She does not care that I masturbate but I do mind for various personal reasons and I want to prevent that as much as possible. Knowing my typical mindset when I give in, I was thinking a cage might help me overcome the urge and improve my self-control. Now, some details that may be of importance.

• The device would exclusively be worn at home, never outside or at work. This means I would typically be wearing it from the time I get home in the evening to the time I go to work the next day and during weekends. I would very rarely wear it continuously for more than 3 days.
• It must be protective enough against stimulation from the water jet of a shower head.
  
• My partner wants to have nothing to do with it. It needs to be reasonably discrete so it does not jump to her eyes, reminding her of its existence, and it must be quick enough to remove for when she is interested in having sex.
• My penis is uncircumcised and is of average size.

Given this, would you have suggestions for a model? Thanks you very much.

 

Thanks for the answer. I have tried to involve her in that, and maybe use the situation for play (she likes to edge/ruin me once in a while), but she says she does not want to have the “mental load” (her words) to deal with the device. Her viewpoint is that she does not mind that I masturbate so ”it is not [her] problem”. It is really the mechanical device she does not like. I think she would agree that I do my thing with the device as long as she is not involved but that would be as far as she is ready to go. I understand her point of view, even though it pains me.

My concern with open bars is that it would not protect much against water stimulation and the temptation might be too much in the shower. But maybe I am mistaken? I know there is no foolproof device but something that would simply make it cumbersome enough to masturbate would probably me sufficient.