Overspending & depression

I'm a male, 44 years old. Wife is 57. Married approx 14 years, together about 22 years. One child 16 just gone to boarding school. Wife has two older kids who I treat as my own (her ex husband paid virtually nothing). Wife always had problems with money, currently has no bank a/c (has run 5 separate a/cs into default over the years). Currently she owes only about £2000 and very reluctantly does a p/t cleaning job at £84 per week. I now and always have worked full time salary approx £30k for a 60 hr week doing a manual job on nights. Wife made redundant 5 years ago (teacher) and pretty much refused to work since despite worsening finances (again).

Originally we had bought a house together but this was repo'd in 1991, I went bankrupt with substantial debts, was discharged in 94. (Wife did not go bankrupt due to pension and career considerations). After my discharge I made settlement arrangements on all her debts. Now I find myself possibly facing insolvency again albeit we are in council accomodation this time. I have approx £20000 unsecured debt all in default (my sole name), no assets, daughter's school fees piling up. Wife spends £150- £250 per week on fags and food for her numerous pets and due to living together and I guess my weak character and a sense of duty I just can't not pay. I pay all bills, car expenses etc. She has an index linked pension worth minimum £100k which she can draw in 2 years - much of this value accrued while with me and it's dawned on me that she is just waiting for this to come on stream and get her state pension.

I can't bear another bankruptcy and am about to leave as I urgently need to get on top of all my debt and take control of my life. I have no pension arrangements and don't want to live the rest of my life like a pauper. Have discussed this with wife but she still won't do anything.

Would anyone be able to let me know if I have a liability to support the wife after leaving (appreciate it's usually a 50/50 split). As I said i'm paying school fees for my daughter (she lives at college and i've offered her the option of coming back to me at the weekends / holidays). I'm aiming to take legal advice but just wanted a few pointers before moving forward. Ideally I intend to leave and simply wait the 5 years to avoid any confrontation. Am hoping that wife will take steps with doctor / counsellor and that the older kids will try to steer her down that route.

Any comments, advice or suggestions would be very gratefully received. I'm working on the basis that if I leave her in a situation where the bills are up to date and with a car so that she can get to or from a workplace there's no reason why she should not get a job and am aiming to try to pay everything for a couple of months to give her a chance to sort herself out. Any ideas on how a Court would see all this?