Her husband’s family told her that he had divorced her but she did not hear that from her husband, and he did not write any divorce paper for her

Firstly: 

If the husband
says to someone else, “Tell my wife that she is divorced,” then divorce
takes place as soon as he says that. It says in al-Mabsoot by
as-Sarkhasi (6/141): If he says to someone else, “Tell my wife that she is
divorced,” then she is divorced whether he tells her about that or not. End
quote. 

In
al-Muheet al-Burhaani fi’l-Fiqh an-Nu‘maani (3/210) it says: If he says
to another man, “Tell my wife she is divorced,” then she is divorced as soon
as he says that, whether the other man tells her or not. End quote. 

In
al-Mudawwanah (2/78) it says: What do you think if a man says to another
man, “Tell my wife she is divorced”; when does the divorce take place? Is it
on the day he tells her or on the day he told him to tell her? He said:
According to the view of Maalik, the divorce takes place on the day he told
him to tell her. I said: What if he does not tell her? He said: The divorce
still counts as such according to the view of Maalik, even if he did not
tell her, because Maalik said, concerning a man who sent an envoy to his
wife to tell her that he had divorced her, but the envoy withheld that news:
It does not matter; the divorce is still binding. End quote. 

Secondly: 

With regard to
the wife, if two men of good character told her that her husband had
divorced her, then she must observe ‘iddah on the basis of their testimony.
If they told her that he had issued a first or second talaaq (divorce), then
she must count that among the number of divorces. If they told her that he
had issued a third (and final) talaaq, then she must keep away from him and
leave him. 

As-Sarkhasi
al-Hanafi said: If two men of good character testify in a woman’s presence
that her husband has divorced three times, and he denies that, then they die
or disappear before they can give testimony to that effect before the judge,
then the woman cannot stay with him, and it is the same as if she had heard
him divorce her three times, because if they had given this testimony before
the judge, he would have ruled that she is forbidden him. The same applies
if they gave that testimony in her presence.

End quote from
al-Mabsoot (10/183). 

In al-Bahr
ar-Raa’iq by Ibn Nujaym al-Hanafi (4/141) it says: If two men testify in
her presence that he (the husband) divorced her, then she has no right to
let him be intimate with her, but if only one person tells her that, then
she has no right to refuse intimacy. End quote. 

In the same
book (4/141) it also says: … If a woman is informed of divorce by two men of
good character, it is forbidden for her to let him be intimate with her;
their testimony alone is sufficient, with no need for a court ruling. End
quote. 

Some of the
fuqaha’ are of the view that if one man of good character tells her that,
she should observe ‘iddah on the basis of what he says, unlike the case if
the one who tells her is not of good character. It says in Qurrat ‘Ayn
al-Akhyaar li Takmilat Radd al-Muhtaar (7/511): If a man of good
character tells her that her husband has died or has divorced her thrice,
then she may remarry. But if an individual of bad character tells her that,
she should double check. End quote. 

But what
appears to be the case is that these fuqaha’ were speaking of such news
being brought by one trustworthy individual on his own in the case of the
husband’s absence. It says in al-Fataawa al-Hindiyyah (5/312): If a
man is absent from his wife, then a Muslim of good character comes to her
and tells her that her husband has divorced her thrice or has died, then she
may observe ‘iddah and marry someone else. But if the one who tells her that
is not of good character, then she should double check. End quote. 

In
al-Mabsootah by as-Sarkhasi (10/179) it says: Based on that, if a
woman’s husband is absent and a trustworthy Muslim tells her that her
husband has divorced her thrice or has died, or if he is not trustworthy but
he brings her a letter from her husband telling her that she is divorced,
and she does not know whether he wrote it or not, but she thinks it most
likely that it is true, then there is nothing wrong with her observing
‘iddah and remarrying. End quote. 

Whatever the
case, you can check with your husband about something that his family told
you of. If the husband confirms that the divorce has indeed taken place,
then you will be certain and your doubt will be dispelled. If the husband
denies it and the one who told you is of good character, then in that case
you have to refer the matter to the Islamic judge (qaadi) to decide about
this difference. It should be noted that divorce does not become finally
irrevocable except in the case of the third talaaq; in the case of the first
and second talaaq, it is still revocable. Before consummation of the
marriage and being truly alone with the husband, any talaaq is revocable; it
is also revocable if the husband issues a revocable divorce and the ‘iddah
comes to an end without him having taken her back, as we have explained in
fatwas no. 118557 and 46561. 

And Allah
knows best.