You should look into the possibility of another man. Very often, when a wife goes frigid toward her husband, she isn't really off sex, she's just off sex with him. She may be focusing her sexual energy on another man. You should rule that out before you do anything else.
If she's still loyal to you, then it sounds like you're a beta trying to increase your beta to attract her. If so, you should add alpha instead. Stop begging, whining, and talking in general.
Look into Married Man Sex Life
for more information.