Max Tyler Hallam, 21 of Mapplewells Road, admitted assaulting Hayley Tryner on 3rd June at the home they shared with their three month old son.
Magistrates heard the pair had got into an argument as she washed bottles for the baby, over £10 she needed for work.
Ms Tryner told police he had grabbed her by the throat, pinned her down and sat on her, pushing a pillow on her face and threatening to suffocate her.
Hallam admitted pinning her down but denied making the threats. The couple have since reconciled.
He was released on conditional bail until 16th July.