Bethenny Frankel's ex has accused her of using him as a sperm donor, Radar Online reported Thursday.

Sources close to Jason Hoppy, Frankel's estranged husband, say that he feels used by her. The two are still living in the same Tribeca apartment despite their split earlier this year. They have allegedly gotten into nasty arguments and one recently became very heated.

"During a recent argument, Jason accused Bethenny of using him as a sperm donor in order to have Bryn. Jason was pushed over the edge because Bethenny is going forward with her plans to win sole custody of Bryn," a source said.

Last week, the warring couple told a judge that they had been unable to reach  a custody agreement. Hoppy is said to be angered by Frankel's desire to have their daughter all to herself.

"In what world does Bethenny live in where she thinks Jason would just walk away from Bryn? It's clear to Jason that Bethenny once she had their child, she got what she wanted from the relationship and she walked away," the source said.

Two weeks ago, Frankel told PEOPLE that she was determined to move on with her life.

"You just just have to say we're going to get to the other side," she said. "I'm not going to be afraid and I'm not going to get more than I can handle."