02/18/2014 at 10:00 AM EST
insists he was not merely a sperm donor to his ex-girlfriend of 10 years, Danielle Schreiber, with whom he's currently locked in a bitter custody battle over their 4-year-old son, Gus.
"I was a willing co-parent and still am," Patric, 47, who hasn't been allowed to see the boy for one year and counting, insists in an interview with PEOPLE. "Danielle and I tried to conceive a child for three years. The only reason we did in vitro fertilization is because she could not conceive naturally. That does not make me a donor."
Schreiber, 41, a massage therapist, argues that that's exactly what Patric was. "When Jason offered me his sperm, it was under the condition that his donation never be made public and that he would not be a father to the child," she has stated. "I chose to use a known donor over a stranger, but only after I knew the law would protect my ability to make the best decisions for my son."
Patric says their relationship soured after he broke up with Schreiber in June 2012, when Gus was 2. Soon, he says, she began withholding access to the boy. After he filed a paternity case for custody a month later, a Los Angeles judge eventually ruled in Feb. 2013 he was a donor and therefore, by California law, not the natural father.
Having abandoned hope at amending the law, Patric is now hoping to win a pending appeal on the custody ruling. He's also since launched Stand Up for Gus, an L.A.-based effort to raise funds for awareness of parental alienation. (Actors Matt Damon
, Kiefer Sutherland
, Jon Hamm
, Sarah Silverman
and others attended a fundraiser for the organization last fall.)
Schreiber, however, has filed a restraining order request against Patric, to forbid him from speaking about their son in public or private without her permission. A hearing is set for April 17.
"I had a loving relationship with my son and it's gone now," says Patric. "Danielle is completely erasing me from my child's life. I'm leaving a public trail so he'll know I did everything I could to be with him, that he wasn't abandoned."