Can 'I have written to him for a long time/for six years' mean I recently stopped writing him?

Question

I have written to him for a long time.

Is it possible to write that? Someone told me that this sentence was not valid, but I don't understand why? Is it true?

It means for me that I still write to my friend or that I have recently stopped.

I want to say that I have very recently stopped writing after sending many letters during a long time, say six years. Is the sentence below okay?

I have written to him for six years.

but I recently stopped.

What difference, if any, does for a long time and for six years make?

If present perfect is not possible here, what tense should I use?

Answer 1

Saying "I have written to him," only suggests that at some point in the past you wrote one or more letters to him. It does not mean that you no longer write him. It conveys no information regarding present or future correspondence with him and very little information on the past correspondence, merely indicating that it occurred to some unspecified extent.

As a general rule if you are going to use specific time frames, years for example, use present perfect continuous.

I have been writing to him for six years but I recently stopped [writing to him].

You may use the present perfect with more generalized time frames.

I have written to him many times but will no longer [write to him].

Both are correct and will be understood.

Answer 2

I have written to him for a long time/six years.

implies that you are still writing to him, unless you say otherwise.

You can use the present perfect continuous/progressive to indicate that you recently stopped writing him:

I have been writing to him for a long time/six years.

But this is ambiguous, because it could also mean you are still writing him. So, to get your meaning across, you need to depend on context or state explicitly that you are no longer writing him:

I have been writing to him for a long time/six years. But that's long enough. Someone else can write to him from now on.

There is no difference in grammar between for a long time and for six years.

Answer 3

When you say "I have written to him", it suggests that wrote a single letter at some time in the past, and the consequence of that action persists (the letter). That's why it sounds odd when you add "for a long time".

If you want to suggest that you wrote several letters over a period of time, you need to use a continuous tense.

I have been writing to him for a long time. (and I still do - present perfect continuous)

I was writing to him for a long time. (but I stopped some time ago- past continuous)

Alternatively, you can suggest that writing to him was a habitual action that you have now stopped, by saying

I used to write to him.