Here I put my 2 cents:
1) Ur Parents may sign an agreement of terms & conditions of service/job & take her as care-taker for their domestic household/ account work.
O'wise they may sign a rent deed. Give her some salary in her account every month. Give her a 'room' also in ur house.
2) Never marry her formally. If bith of u r in mutual understanding, its totally safe relationship. Keep her parents in confidence & be true to ur word also.
Regarding legal issues:
1) Married man has s*x with unmarried/divorced girl----- amounts to adultry. If wife reports in police, its non-cognizable offence, police will not lodge FIR, practically no trouble. At the most, ur wife may make it as a ground 4 getting divorce-- all rewards!
2) Married man has s*x wid others wife, its a punishable crime for u & not for that adulterous wife, thats why ppl here are insisting that concentrate on her divorce to be extra safe. Meanwhile, if both of u play safe & remain true to ur word--- rewards!
If these points are adressed, this is the best deal possible 4 both of u in these circumstances! CHEERS