Can wife file rest of conjugal rights after 18 years seperat

Apparently; yes and there may not be limitation.

Marriage is union of two sojld and sacrosanct and may not be looked upon just as some contract and separation might be due to differences on trivial matters, without a  proper reason, and reunion might  be possible.

This is essence of the matter.

Rest the burden may fall upon petitioner (one spouse) to prove that respondent (other spouse) has left her/him without reason and if proved burden may shift upon respondent to prove that IT is practically impossible to stay with other spouse and marriage is irretrievably broken down.

The court shall decide the matter and look into precedneces.

One should avoid falsehood and rather build on evidences, provisions of law, precedences.

Rest is upto you.

She can.    But the decision will be in your favour.

She can.    But the decision will be in your favour.