negative equity mortgage with friend, im no longer living in house

I purchased a house with a friend as an inverstment in 2006. I had been living in house with my friend until I got married in 2011. Now renting with my wife elsewwhere but want to buy our own house in next few years. My friend wants to remain in house and to take sole ownership which he can afford to do, but wants money to do so (we have not agreed to an amount yet)
How should I go about getting my name off the morgage and is it possible? will it affect me if I apply for a new mortgage with my wife in the coming years, I feel a bit trapped at the moment but realise my obligations and have kept paying my way.

Mortgage remaining €280000 (No arrears) Value of house 160000

Mortgage term remaining 22 years

Income 32K €2100 per month

Friend income 50K

Wife income 55K

Just finished wedding loan so can start saving €400 per month

home improvement loan 12K finishes next year I pay €250 per month(half of loan)

mortage per month €1600

2 rooms rented €550

I pay €300 towards mortgage as the rest of my half is covered with rent a room.

rent €900 per month with wife I pay half.

Can anyone please advise on my best options?

Looking at this from the perspective of the Bank/BSoc I feel that you will have a lot of difficulties extracting yourself from this loan. House is in negative equity of c120K. Currently both of you are jointly liable for the mortgage. The Bank will need a good incentive in order to allow your name to be removed from the loan. Assuming that your co-owner is not an extremely generous sole he will also need to be re-imbursed if he is taking sole responsibility for the loan. On the assumption that both parties have a reasonable level of income and are relatively solvent otherwise the Bank would expect a minimum reduction of 60K in the loan amount (50% of negative equity) before such a proposal would be considered. However, your'e first action is to set up a meeting with the Bank and make your request. You never know, what their response will be until you ask!