Been seeing a new bloke casually for about 8 months, although I've known him for another year on top of that, and have known his mum for about 15 years. When I say casually, I mean we've been at the same parties, been out for drinks in a group etc and he's pretty much always ended up back here 
It's been slow because he's going through a divorce and didn't want to make the process worse by flaunting a new gf iykwim.
Anyway, it's all ok now and we had our first official "date" last night and were chatting about holidays next year and stuff. He asked me to go away for the weekend next month and I said I'd ask ds's dad if he was free to have him and he said it wasn't a problem to bring him along. I said I wasn't ready for that yet, as I've never introduced him to another man and I want to make sure he's a permanent fixture before I do. Which he was fine with.
Made me think though; when is the right time? We're only just officially a couple, but I knew months ago that he was the man for me, and I know him pretty well. There's no rush, but obviously it will make things easier when ds knows, as we won't be having to arrange things around when he's at his dads house.