As the log book is in his name, he is the registered keeper.
If you asked him for the car because you have paid for it, would he be likely to keep it or hand it over, if this as an acrimonious seperation and you think it will need to go to court to split your assets, you will need to bring up the matter there and prove you took the loan out and have made all the payments.
It is much easier if you can sort these things out between you but would have been even better if you had registered the car in your name, but I know, you never think you will have these problems.
