Hi I need to have a hot shower with out being interrupted as the water goes cold when my wife uses the hotwater to wash up in the kitchen the shower changes to cold water can something be done about it thank you

The only solution I have ever came up with is saying "I am going to take a shower now''
Which translates D0 N0T use any water until I am done.

N0help

You could run a totally separate hot water line from your water heater directly to your shower. Would be much easier and cheaper to do what Nohelp4u mentioned,that's what most people do,you could also plumb in a separate water heater just for your shower.

You need to have the shower valve replace with one that that the water temp doesn't change just the water pressure. Example flushing toilet you burn or kitchen facet turns hot water on you freeze. I think its called a mixing valve but not sure