To ask how much I should pay towards this?

[Undecidedandtorn]

I split up with my ex a year ago but we have been sharing accommodation (2 places swapping every week with the kids staying in the same house). The hot water in the main house broke just before Christmas.

Due to having an old set up (no central heating) it took a while to find someone to install a new set up which finally happened about 4 weeks ago. I'm moved into my new place on Friday so now we won't share accommodation and the kids will spend 50% of thier time at each of the places.

The water heating system cost £1500 and I'm really broke at the moment. My ex paid it out of our joint account which we both were putting 2/3 of our salary into (so me 60% him 40% of the total monthly amount that went into the joint account). I don't feel I should pay anything and he should refund me my share , he thinks I should leave as is.

What would a fair amount be?

If it wasn't your house when the work was done and bill was sent then its not your liability. You put up with no system for months, and what now you get to pay for the repair but don't benefit. No I think he needs to refund you, its not your responsibility anymore you have your own place to pay for. Presumably he can afford it.

@Johnnysgirl so the ex should go around cataloging everything that broke/wore out/deteriorated whilst the OP was living there and charge 50% now? Why not? How are carpets, an old fridge, cracked loo or burnt out lightbulbs any different?

Am I right in understanding you have a joint account as well as separate bank accounts and that he took all the cost of the new boiler abs system for his house in his name, out of your shared account not his own?

Really he should pay it back and I would be asking for him to return what he took. Ultimately you can take him to small claims to get it back as you'll be able to show he used joint money for himself. However if things have been amicable I would negotiate with him so that you contribute but don't pay 50% as it's left you short and wasn't your cost to pay for.
He knows he's been a CF

They we're both living there when it broke? Doesn't matter when it was actually fixed, really. If it had been fixed immediately it would have been 50:50, I don't see why delaying the replacement until op had moved out makes it her ex's sole responsibility .It's not a cosmetic enhancement, it's necessary maintenance.

No she was living elsewhere, they were merely previously swopping for a childcare arrangement.
It's his house in his name and his responsibility.

Unless he's paying equally towards OPs home then he's taking advantage of her to take the whole cost of upgrading his boiler hot water system after she was no longer living there, without agreeing it as a shared expense. He just helped himself after she had left

This is tough. If i were him i would not ask you to pay, for the reasons you gave, he can enjoy this for 20 years. In your position i would discuss it with the potential to offer something up to half towards it, and perhaps including in the discussion the need to have a good, amicable relationship going forward. I would be hoping from that discussion that he would see he was benefiting financially and that there might be ripples from this down the line.

The OP said they were sharing homes and swapping between homes, so I think they should split the cost.

Now, draw a line under things and you are responsible for your own houses.

You came off the deeds with no legal advice..?