Certainly sounds like something is going on.
My OH is obsessed with his phone.
He takes it everywhere and hides what he's doing on it
He works late, goes to the office on weekends
stays overnight at his friends some weekends
Do you know where he works? Could you verify that he's actually working?
He runs errands that should take 10 minutes but is away 30 minutes or so.
We've got a house in his name and 4 children.
Not married? I see why you're stuck and unhappy. Unless you can prove you've contribute...the house is his.
How is your relationship?
Are you close as a couple? Do you have a good physical relationship? Is he involved in family life with the kids?
Do you work?
Do you ever get to socialise? Do you stay at friends houses overnight?
I suggest you start investing time in yourself.
Look good. Get fit or stay fit.
Get out of the house. Live your life and leave him to it.
He's clearly not happy in the relationship and neither are you.