What evidence is there of tension between Stanley and Stella? According to Stanley, what is the source of this tension? Scene 8-9

In Scene Eight, as the dismal birthday party is wrapping up. Blanche has been stood up by Mitch. Blanche feebly tells a joke, and it falls flat. Stella criticizes Stanley's table manners, and he loses his temper, shouting that Stella has been showing him too much disrespect and calling him too many names since her sister got there. He stalks out.

Blanche tries to get Stella to tell her what happened while she was bathing, but Stella refuses. Blanche telephones Mitch, against Stella's protestations, and leaves a message. Stanley returns and embraces Stella, saying everything will be alright once Blanche has left and they can have privacy again.