is this marriage a valid one after 7yrs

It has not deviated from the original track. Adultry is only if there is a legally sustainable marriage. If the  man is not legally married, he is not guilty of adultry. So the question of validity of marriage is relevant.

Secondy,she wants to get out the relationship with the guy and sought advice. From  the wordings of her query, it appears that she is not married legally. If that be the case why go for complicated procedure for divorce?

The best course for her is to assert that there is no subsisting marriage and ask for divorce only if he proves otherwise. Especially since her apprehension is based on what seems to be just a notorised agreement that does not constitute legal marriage.

If a married man had s*xual intercourse with a woman, who is not his wife and who herself is not married, it will not amount to adultery under IPC Section 497.

The lady has still not explained what she meant by a "court marriage". Until she answers that question no advice can be given.

I think the author is lying somewhere as if it is Court marraige,  there arises a burden on the part of marrying couple to establish that they had been as per hindu rites and rituals, or something like marriage cards, photographs or whatsoever,even if the marriage has been solemnized without the knowledge and consent of parents  ( in context to H.M. Act, 1955), and as per the author the marriage as such solemnized is a Court Marriage, the substantiality of marriage become undisputed so whatever the discussion shall be posted hereinafter hereinbelow shall be kept in mind the substantiality of marriage as an undisputed fact.....