@Anonymous User Welcome to the community. Yeah it's an issue that crops up quite a bit. Some people have suggested setting up a second account with a different pass on each but if they all want to watch the same type of pass that doesn't work (unless you have the same pass on both accounts and double up payments) and it's also a faff logging in and out of different accounts so you'd have to decide if it's worth trying that or not.
Also bear in mind the two stream limit only applies to the NOW TV app, so you could have two children watching NOW TV while the third watches BBC iPlayer, ITV, YouTube etc. Until NOW TV add extra streams not much else you can do.
