It sounds like your work from home is the kind of situation where you do a full day's work at the office, and then bring work home to finish up in the evening/on weekends, right?
That's a totally different situation than your ordinary work from home commuting. It's also very common in my field (academics) where you are evaluated on performance, not hours, and the amount you need to do to succeed is more than a 40 hour work week.
It's really easy in a situation like this for your work to take over your home life, too. You're working, and your SO/kids are getting brushed off with "Don't bother me" when they want to spend time with you. It's worse if you're doing something that requires mental concentration, rather than just physical stuff. If you're doing something low mental effort, you can respond to questions about home-work, or be interrupted by comments, rather than checking out from the evening activities completely.
If kids are an issue, one option is to work after the kids are in bed. So you get dinner and some relaxation with the kids, and the bed-time routine, and as soon as they are in bed, you pull out your work stuff.
Another option is to put a stated time limit on your work hours, particularly on the weekend. So you tell your family "I need to work from 1-4 pm, but after that we can do X", and then go off into your work corner, and when 4pm hits, you leave your work behind.
A third thing to try - schedule your high concentration work for the office, and lower concentration stuff that can be easily interrupted in the evening, so you're at least partially present for the family, mentally.