To be angry at my ex for not telling me

[flatpackfurniture]

(NC for this as worried about being totally unreasonable here...)

So a quick bit of background-
I have a 3.5 year old DC. Me and DC's dad broke up when DC was about one because I found out he was having an affair (which had begun days after I gave birth)

DC's dad then started having minimal contact with DC (his decision) and I've raised him single handedly other than DC's father seeing him every once in a while. I also get no financial support from him.

Anyway, DC went to his dad's house the other weekend for a sleepover (rarely happens) then when he came home, started going on and on about his dad's girlfriend. (The same woman he was cheating with)

I think this is the first time they've met, and I'm furious that DC's father never mentioned to me that DC would be meeting her. He could of at least MENTIONED it to me??

I want to bring it up with my ex how unfair it was for him not to tell me but I'm not sure if I'm being unreasonable or not. He hardly sees DC, doesn't provide for him, and yet he did this which I feel should of been run past me first.

I'm probably being seriously unreasonable as I know they've been together a long time now. I just thought I'd check first before I open my gob

I don't know why people are being harsh on OP she asked a question which most don't seem to be answering.

I think he was out of order to not at least discuss it with you first.
I’m not sure what’s happening on MN at the moment (been away and not long come back) but there seem to be a hell of a lot of posters defending really shitty men, when in reality, it’s just excusing deadbeat crappy behaviour towards women and their children.
He isn’t a parent in any other sense than biologically from OPs post, he doesn’t contribute in any meaningful way, and I think you have every right to be hacked off about a big thing being dropped on your child without prior warning to either you or your child.