looking for some advice, and if anyone has been through similar. I've posted on here several times and always found it so helpful (although not sure of relationships is the best place? )
anyway some quick background first...exp left me when I was 5 months pregnant, 4days before we were due to move in together. I was left no where to go as I had given up my flat and the house was in his name. also turned out he had been cheating on me the whole time anyway with his previous girlfriend 

we had little contact throughout the pregnancy, I was devastated to say the least and after DS was born he had regular contact and has him every weekend (I chose to work weekends as childcare is too expensive)
exp repeatedly tried to make a go of things but I couldn't after the torture I had felt and after seeing how very unpleasant he can be (refused initially to pay CM because 'your breastfeeding, it doesnt cost you anything
amongst many other things) but he didn't take it well that I would not get back with him.
so fast forward to now, things are generally ok, we get on well enough for DS sake and I have moved on, found an amazing partner and things are fine. my problem however is exp, he works in a very well paid job, and has ten flats which he rents out. I privately rent which is a fortune and work full time but it is a struggle and after all the bills are paid have virtually nothing left, and as much as I hate it, I really depend on the cm I receive from exp to help pay rent and keep a roof over our sons head (and mine) so on sunday when I received a text from him saying he cant give me the money for another week when it should have been paid in the previous day and my rent is due to be paid the following day imo is not good enough!
we had an agreement that it would be paid on a certain day each month as he knows I need it for rent. but what made it all the more galling was his excuse. "I have spent thousands of pounds every week for the last few months on renovating two of my flats and it has sucked me dry" 



I can't afford to get messed around with this as it means paying rent or not!
I was very unsure aboutt telling exp about DP as I wasnt sure how he would react. I left it until a while after he had announced he was seeing someone (a 22yo. he is 37!) I can't help but feel this is because I have recently mentioned DP for the first time. I could be wrong of course, but my gut instinct, and knowing him well tells me otherwise.
I always drop DS and then collect him when I finish work on sunday, I wasnt well and was off work so asked if he could drop DS to which he first point blank refused then eventually agreed but said he will deduct £20 for petrol from the already late CM!
arsehole!!!
so now he has demanded that he has DS next Christmas eve into Christmas day but our agreement from day 1 was that I would have ds those days and then exp get him boxing day for four or five days.
I cant help but feel he is bullying me with the money situation. he has deducted money once before. and now is just causing grief. so does anyone know of what I can do about this ie something formally written by a lawyer re CM and holidays? it is causing me no end of stress and all I want is some consistency
apologies for the badly written thread, im at work and trying to write this inbetween breaks without reading back, thanks for reading this far