I don't have a phone, so I don't turn it off... My situation is different since I live with my husband but am in a long-distance relationship with my boyfriend.
We haven't been able to keep up with date night, as they are both so busy right now, but when we did we simply scheduled my dates with Sean on days Rag worked (he works 18 hour shifts, from 1pm to 7am the next day, 7 days per two-week period). Then I had all of my time and attention for Sean and turned off all other programs on the computer.
On my dates with Ian/Rag, I wouldn't log in during the date and therefore spent it with just Ian.
It's rather easy for me to separate them, really the problem is the other way around. Pretty much impossible to do things will all three of us together. For that reason I can't wait for Sean to come and visit us in December, so we can watch movies or play games or just talk with all three of us involved. Of course I would still have one on one time with both of them as well.