- I want to go and leave you.
- I want to go and to leave you.
Which one would be accurate?
Neither is wrong, certainly not for common use of English. The second sentence is a much less common construction, in my experience as a native speaker in the United States.
The first sentence suggests that both actions are combined in some way:
I want to go, and by going I will leave you.
I want to leave you, which I will do by going.
The second suggests that the speaker wants to do both things, specifically:
I want to go, and I also want to leave you.
There is also a common use of the phrase go and which usually does not convey much information other than that someone chose to do something:
Why did you go and do that?
In those cases go and could be completely omitted and the meaning of the sentence would not really change at all. I don't think that that pattern is in place in the first sentence in the question, but I wanted to distinctly mention it because it's likely that you will come across this specific usage of go and at some point.