London: The husband of the murdered MP Jo Cox has resigned from the two charities he set up in her memory after being publicly accused of sexual assault.

Brendan Cox has stepped down from his posts at More in Common and the Jo Cox Foundation after allegations, printed in the Mail on Sunday, that he assaulted a woman in her 30s at Harvard University in 2015. Police filed her complaint as “assault and battery” but action against him was dropped.

Cox said it had become “much more difficult” to focus on his charity work after the allegations came to light. In a statement issued on Saturday, he denied the claims but admitted making “mistakes” in a previous role with the charity Save the Children.

“I want to apologise deeply and unreservedly for my past behaviour and for the hurt and offence that I have caused,” he said in the statement.

“In the aftermath of Jo’s murder, I promised that I would dedicate my life to two things, firstly loving and protecting our children and secondly fighting the hatred that killed Jo.

“In the last few days, allegations from several years ago have resurfaced that makes concentrating on both of those tasks much more difficult. For that reason, while away over half-term, I decided to step down from my current public roles for the time being.”

Jo Cox, a Labour MP, was shot and stabbed outside her constituency office in West Yorkshire by a far-right extremist during the EU referendum campaign in 2016.

In the statement, Cox added: “While I do not accept the allegations contained in the 2015 complaint to the police in Cambridge, Massachusetts, I do acknowledge and understand that during my time at Save the Children I made mistakes.”

Cox, who married his wife in 2009, was reported to police in Massachusetts in the US in 2015 for “inappropriate touching” while on a trip to Harvard. A woman alleged he had bought her drinks, grabbed her hips and forced his thumb into her mouth in a sexual manner, the Mail on Sunday reported. Cox denied the women’s accusations and called some of the allegations against him a “massive exaggeration” but said that in his previous role at Save the Children he had “overstepped the line”.

The Mail on Sunday reported in 2015 that Cox had stepped down from his position as chief strategist after allegations of “inappropriate behaviour” before a misconduct hearing.

Reflecting on his past behaviour in an interview with the Mail on Sunday, he apologised for any “hurt and offence” caused. “Certainly, I had too much to drink at times. I probably behaved in a way I thought was sort of jokey or flirtatious. I often wasn’t being serious, but that was perceived differently by others,” he said.

“There was never any malice; any intention to upset or offend people. But the bigger picture is that you do have to face up to how you make people feel, not just what your intention was. I didn’t reflect on it — that’s not a defence, it’s a failing. It’s not good enough.”