It's fun to switch from one to another, but it would be an even better, and frankly more logical combination,to choose which character you want to root for (so that you improve a specific female npc's attraction towards him), and to choose events that cockblock the other npc).
So for example, if you choose to root for the son, you should do everything you can to improve your relationship with Tasha, and when he's away on his school trip, you should have the option to worsen her relationship towards his dad.