So annoying- why doesnt my network get switched back

Why does my wireless connection switch to Xfinity network sometimes specifically overnight and not switch back to my dedicated home network. I’ve noticed when  I can’t access internet channels or streaming apps (like Hulu) it’s on  the Xfinity network so I have to go into settings on my tv and switch the network off Xfinity to my home network then all works fine .  It’s so annoying- if it can switch to Xfinity why can’t it switch back to the home network without me having to check