The ill-feeling develops when Peter confronts Ian over his refusal to make an effort with Whitney, explaining that she means a lot to him and he should try harder.
Later, there's another confrontation at the celebration as Ian and Jane argue over money. Peter steps in to defend his stepmum, but the conversation soon turns back to Whitney - and Ian cruelly brands her a walking STD.
As Peter angrily storms out of the party, it's clear that relations in the Beale household are currently in a bad state…
EastEnders airs tonight at 7.30pm on BBC One.
> Click here to read more about tonight's episode