six year after the separation is no ground to avoid maintenance to wife. even after divorce wife is entitled to maintenance untill and unless she remarries in that case burden shifts on to some other person who replaced you.
following are the circumstances where maintenance is not allowed and liability of husband doe not lie-
1. prove in the court that wife is well euiped to mainain herself or she has enough means to maintain herself as onnly those wives are entitled to maintenance who are unable to maintain herself. or
2. she is leavingr separately or avoiding the company of the husband despite his offer to maintain her on condition that she join him, without any just and proper reason or
3. she is leaving in adultry.
In your case your wife is equiped with high profile degree and with this she can get decent job. you can press this point in the court. there array of judgements of higher courts on this point