One suggestion is to tell your difficult child that you need some quiet time so that you can think and do what you need to do. You can also tell him you need time to talk with Dad. I'd tell him that you need your quiet time 3x per day or else....you'll go crazy. Set up a timer and tell that he needs to find something to do for ten minutes. I'd set up some type of chart and reward him just after a few times. And if he can acutally do it, it will help him with his need to play independently. I'm sure you're thinking charts don't really work etc....but just give it a chance. Maybe set up the chart on big paper and let him know about this new program. Say it matter of fact and then within an hour or so, let him know it's your time for quiet and see what happens. It may actually work--
Clearly this isn't a new idea or strategy but it just may work because it's simple and new.
Glad to hear the year started off well--