Could all the lovers out there explain the son to me? (up to ep 4)

Only on episode 4 so far

Maybe my cynicism of head-over-heels love is limiting my imagination here, but why was the son so love struck to the point of stupidity? With so much money, why does he not have a radar for gold diggers? Cherry’s lies just roll off the tongue, why would you trust someone so quick to let them live with you?

The mum in episode 3 says they’ve only been together a couple of months