"This is it now, it is all over for me," said father-of-two Mr Molloy, from Childwall. "I've been fighting for over 6½ years for my children to have contact with their father. In that time I have been heavily involved with fathers rights activism, which I am very proud of.
"It has not helped me in the family courts to be a father's rights activist and it has probably hindered my chances of seeing my children, but I couldn't stand by and let people walk over our rights."
After leaving F4J, Mr Molloy helped set up the Equal Parenting Alliance, serving as deputy leader and planning to stand at the next general election.
The party campaigns for equal contact rights for both parents.
But last night Mr Molloy said he had resigned from that position as well.
He said:"I need to rebuild my life and I'm currently looking at the options of moving abroad to either Australia or Canada."
In 2004, Mr Molloy claimed he and another member had been thrown out of F4J after disagreements with its main London branch. Co-activist Dave Humphrey said the pair had been expelled for refusing to wear their Santa suits in court.