Currently my 12 year old stays with me 4 nights per week. This was increased to 5 last week for a trial period. This has all come about since his mum moved her boyfriend in who is a recovering heroin addict. We have a child maintenance arrangement that was agreed over 5 years ago when our son only stayed at mine 1 night per week. I have notified his mum that I will be reducing the child maintenance in line with the government website calculator. She wasn't happy about this and she said she wouldn't be able to afford to live if I did that and she would have to downsize. I suspect her money is getting spent elsewhere but that's another issue. Her and her boyfriend don't work so receive full government entitlements. Plus I don't think he should be living there anyway and they should declare it. Anyway this seems to have panicked his mum and she is now saying she only wants him staying with me 3 nights but he wants 5 and to be honest I think he is better with me and everyone else agrees.

I have said that we will all sit down and discuss things and the boyfriend of less than 8 months wants to too. I said if we can't agree then the next step is mediation which she didn't like. She said all this is making her poorly. My other concern is that none of the maintenance is getting used on my son. I had to buy his school uniform and I buy the majority of clothes for him as well as other things.

Any ideas how I should attack this? In all fairness I'm not right happy about her having a ex heroin addict in the house who has taken methadone in front of our son. I could actually go for full custody but I think this isn't the right way as of yet.