OK, well, I think it's under control enough for me, occasionally dh gets pissed off with it but mostly it's ok. Here's what I do, don't know if it'll help at all:
During the week I work ft so I can't come here during the day at all, ever. I just can't so I don't! I sometimes come on at 6am if I wake up before the children or while they're getting dressed etc but only if I'm drinking coffee/eating my breakfast at the same time and there ISN'T other stuff to do. But usually there is and mostly I don't come here in the morning. Sometimes I'll come on at 7.30am if I'm completely utterly ready and so are the children.
When I get back from work I check my emails first and then come here in a short burst IF ds and dd are occupied/watching telly/playing with each other and when I've done the obligatory 'how was your day?' to which the answer is often 'ok, can't be bothered to tell you' from ds, who is 9 and at that stage!
Then it's mostly once they're in bed and after dh and I have had supper. Sometimes I'll be here 2 hours, sometimes an hour, sometimes 3 hours, depends really. Dh isn't here one night so I'd usually be here until 10pm that night.
It is addictive and it is hard to do only 15 minutes, I rarely manage it.
At weekends, it depends. We have broadband and a pc in the front room so I can pop here whenever ds/dd are occupied/out with dh/asleep in dd's case. every other weekend I only have one child as ds goes to his dad's so that makes a difference. Sometimes I'll come here for a coupla hours, sometimes I won't make it at all if we're out. But I'm usually here first thing on Sat and Sun while children laze about in pyjamas.
When I was a sahm it was much harder but I used to make myself do the ESSENTIAL stuff before I came on so it didn't matter if I was here for hours. HTH.