Dear amit the GENTLEMAN was referring to explanation given in IPC498A and section113a of evidence act. I am pasting from explanation given in IPC 498A which explains the difference in treatment given to marriages less than 7yrs old vis a vis the olderones
"Section 498A vis-a-vis section 113 of Evidence Act
Section 498A of the Indian Penal Code or section 113A of the Indian Evidence Act has not introduced invidious classification qua the treatment of a married woman by her husband or relatives of her husband vis-a-vis the other offenders. On the other hand, such women form a class apart whom from those who are married more than seven years earlier to the commission of such offence, because, with the passage of time after marriage and birth of children, there are remote chances of treating a married woman with cruelty by her husband or his relatives. Thus, the classification is reasonable and has close nexus with the object sought to be achieved, i.e., eradication of the evil of dowry in the Indian social set-up and to ensure that the married women live with dignity at their matrimonial homes; Krishan Lal v. Union of India," 1994 Cr LJ 3472."
Now pasting from section113A of indian evidence act
113A. Presumption as to abatement of suicide by a married women -
1113A. Presumption as to abetment of suicide by a married woman.- When the question is whether the commission of suicide by a women had been abetted by her husband or any relative of her husband and it is shown that she had committed suicide within a period of seven years from the date of her marriage and that her husband or such relative of her husband has subjected her to cruelty, the court may presume, having regard to all the other circumstances of the case, that such suicide had been abetted by her husband or by such relative of her husband.
For the purposes of this section, "cruelty" shall have the same meaning as in section 498-A of the Indian Penal Code (45 of 1860)."