In The Crucible, what is the deal with John Proctor and Abigail in Act One?
An important 'deal' between the two of them is John's wife Elizabeth. They even refer to her in this scene. Abigail sees John as a stud. She thinks he is going to waste because his wife is not that hot. Abigail describes her as "sickly" whether that means in looks, attitude, or actually her health, we don't know.
As John defends Elizabeth, Abigail defends herself by noting that Elizabeth is talking trash about Abigail in the town.
John seems to want to be a man that does the right thing which includes being loyal to his wife now even though he made a mistake in the past. Abigail thinks his marriage is a lost cause anyway, so why not have fun? This incident between the two of them triggers much of what happens the rest of the play. Enjoy the drama.
I do not know for sure what you mean by "what is the deal," but I assume you are asking what their relationship is to one another and why they are acting the way they are.
The relationship between them is that they had an affair back a few months ago when Abigail was working as a maid for Mrs. Proctor. John Proctor eventually broke off their relationship. Abigail is still somewhat in love with John. She still wants him and she does not believe that he has stopped wanting her. So she is trying to get him back and he is trying to convince her that it is over between them.
I hope that is what you were asking.