STBXH pays maintanence based on his income. It's a large amount because his income is large, it's the cms minimum.
Private arrangement, but based on that calculation.
We co parent well, and he is happy to pay this amount plus he does an online shop once a month with stuff for our DD. Nappies, baby food, toiletries etc before and now that she's a bit older, some nice treats, a couple of staple items and sometimes a nice toy or magazine or some glitter pens if they stock them and around Mother's Day he also sent a bunch of flowers and a bottle of wine which was lovely of him. He also takes her to a soft play group which he pays for and he gives me a small cut of his yearly bonus. About 5%, to go towards something for DD.
this has been the case for the last 2 years on the first year it went towards a few experience days and museum visits and a trip away for myself and DD which STBXH was happy with this year it's gone on DDs first proper bed. (She did have one of those cots you can turn into a bed until this year).
We sometimes go out together - with DD and his GF too. Nothing dodgy, just maybe go and feed the ducks and have lunch together. We (STBXH and I) think it's good for DC to spend some time with us all together once a fortnight or so. Gf is very welcome in this btw. I'd never stop her coming.
GF can be very snide about me.
She has made a few comments and has snubbed me when I've bumped into her alone. I get it, she dislikes me, she doesn't have to be around me (while she is invited out with STBXH, dd and I she never has to come, it's an invite not a summons as mn would say).
But if she wants to be around me I will be nice and civil.
Yesterday we all took DD out and while DD was feeding the ducks we were sat on a bench watching her from about 6M away. STBXH went to the toilet so it was just me and GF.
Gf said she wanted to have a word with me about something, I said well er go ahead then.
Gf then started ranting for a couple of minutes about how I take all of STBXH s money 
and she thinks I trapped him (we were married for 10 years 
) she thinks he's far too generous and he should just leave me destitute and if it's up to her DD will lose her dad when she gets pregnant and they will replace her.
She's sick of not having money for x y and z as we "take it all" from him and she hopes I fuck off soon.
I just replied actually I don't take anything, he pays the cms calculated amount and provides some extras at his own will. He likes to provide for his child well and see her in a good environment rather than us struggling, if you hate me so much you'd probably be better off leaving STBXH name because dd is a permanent fixture, much like STBXH involvement with us is.
She stalked off towards the toilets as STBXH came out, said something to him and looked like she was crying. I got dd and went over to talk to STBXH and he said I dunno wtf her problem is but I better go and find out and walked off. Dd and I came home and he hasn't said anything about the incident.
I'm honestly shocked at this level of venom.
Aibu to think she's a 18 carat dickhead?