divorce buy out settlement

[Tom50]

14 years ago my now ex wife left me and our two children, I got full custody of children but in a vulnerable state and desperate to keep a roof over our heads I signed a minute of agreement giving her a sum of money when the youngest child reached 16 years of age. This time is fast approaching and I don't really have the means to pay. I have never received maintenance money from her in all these years as she claims invalidity benefits. I have never stopped her seeing the children on agreed days.It seems unfair that I now have to pay her when I have been working all these years and looking after the children and house. I could not afford to buy her out at the time. I have now moved on and remarried, and no longer live in or own the family property in question of buy out. No money was made in sale of this house although the minute of agreement calculated 14 years ago said a certain sum would be made and that money split, based on housing market at that time. It feels as though I.m having to go through all this again, while ex wife lives on benefits. this is the life she chose when she walked on me and our two young children. I know I have signed a minute of agreement but I feel this was ill advised and also I was in desperate situation and not thinking clearly. Is there something I can do?

[Law Student 7]

Hello, thank you for reaching out to our service. I understand this is difficult for you and will try my best to assist you. You may try to apply for a motion to modify. Are you able to provide more details about this agreement? In addition do you still have a copy agreement, is there a clause or clauses referring to if you are not able to provide the money?

[Tom50]

It is a minute of agreement with Registers of Scotland (Books of council and session) It is an agreement that I pay ex wife£10,000 and I got sole rights of dwelling, she was to be paid this sum on my son's 16th birthday.
I do still have copy of agreement and there is only a paragraph saying that this provision will continue to apply irrespect of any alteration in the circumstances of either party.

She left the family home, leaving me with kids, never paid any maintenance for them and I was just trying to hold things together for the kids. The house in question I sold and barely a profit was made, money made just paid legal fees. The 10,000 was calculated as half the profit we would make on the house if sold in 2007, however I sold in 2013 making very little, certainly nowhere near the 20,000 predicted in 2008.