Amend a tax return from 2005 &06 from married filing joint with my x-husband I divorced Jan 9,2007.Is it legal?

Official Divorce Jan.9,2007.My x-husband duped me into Divorcing after 2006.I had my husband now whom I married oct.07 but we bought My x-husband out of a House contracted to be built to be nice in june 2006.My x filed our taxes joint for 05 & 06 when I made $100,000 he made $90,000.But he put $4,500 into an IRA every year knowing we would pay a penalty.He has a 401k that he put $6800 into in 04,05,06.Probably back to 2001.I paid $22,000 in federal taxes 05,06 he paid $2g only .Can I go amend my returns and if so how far back.I was duped by him putting $ in his 401k,and an IRA in his name.I just want to File married but separate ,CAN I amend 05,06.My new husband bailed him out of a house we lost 120g on & he was paid on a w2 and had his BOSS/FRIEND not with hold Federal & state taxes sticking me with paying his taxes while he stashed $50g away in 401k's & 10g in an IRA