I have not gone. But I *have* gone!

Question

Let's pretend that you recently started working for a company. This company has a yearly Christmas party, and you are wondering whether you're expected to go.

You:

Are we expected to attend these Christmas parties every year?

Coworker:

I have not gone before, and my boss still loves me.

As a native English speaker, there seems to be a frustrating ambiguity. Your coworker could mean:

I have never gone, and my boss still loves me.

Or:

There have been one or more years in which I didn't go, and my boss still loves me.

In English, it seems that "I have gone" doesn't imply having always gone, but "I have not gone" does imply having never gone.

Is there a concise way of indicating the opposite of "I have gone"?

Edit:

By opposite of "I have gone", I meant the opposite of what it conveys.

"I have gone" conveys:

One or more times, I have gone.

The opposite would convey:

One or more times, I have not gone.

Answer 1

I have failed to attend before.

or

I have been absent before.

(Basically, any sentence where you can embed the negativity into the semantics into one of the other words (such as fail or absent) — rather than using not — will eliminate the ambiguity of where not applies.)

Answer 2

This is a tricky area of English grammar. I think we might be missing a tense or something.

Your original phrase I have not gone before... does mean what you want, but it's a variation many people would not pick up on. This is because the not can bind to both have and to gone, but most native speakers will assume it binds to have. To make it bind instead to gone, you have to split the clause.

An experienced, native speaker would probably say I have sometimes not gone before... which naturally conveys the meaning you want. Even if it would sound awkward to some speakers.

Answer 3

You don't have to talk about it in the past tense. You can describe yourself, rather than describing your past actions. The most natural thing for me to say is

I don't always go

Answer 4

This is one of those cases where the fact this is a spoken conversation (unless you're doing this over email or text) is critically important. The emphasis of the "not" and where the pauses are will tell any one listening exactly what they mean. If your coworker says

I haven't gone before...

slurring the "not" into the "have", and thereby negating the "have", then they mean they have not, on any occasion, gone before. If they say

I have ' not gone before...

Avoiding slurring the "not" and pausing slightly before saying it (the apostrophe in the quote), and thereby negating the "gone", then they mean they have, on at least one occasion, not gone before.

For completeness, if they say

I haven't not gone before...

they mean they have not, on any occasion, not gone before (i.e, they have always gone before) while

I have gone before...

means they have, on at least one occasion, gone before, as you state yourself.

Also: In text conversations (like email or text) the "standard" is to use -n't to negate the helping verb (have, do, be, and various modals) and fully written "not" to negate the actual verb ("gone" in this case). When reading your quote, I see no ambiguity - the coworker speaking has, on at least one occasion, not gone before.
However, I realize that formal written media (like dissertations or essays) sometimes forbid contractions, meaning that only "cannot" vs "can not" remains. In these contexts, @Kosmonaut's answer is better, as "not" is then assumed to bind to the helping verb (unless it's "can").