The trial of a 44-year-old father of two accused of murdering his wife during a family boating holiday four years ago, today, Tuesday, heard from a college lecturer who maintained he'd been her lover.

And the lecturer, who said he had a sexual relationship with Lu Na McKinney rejected defence claims he "imagined" the affair.

Dungannon Crown Court has already heard Lu Na's husband Stephen McKinney described as a controlling man unable to face the prospect of her divorcing him. Originally from Strabane, but living with his family in Convoy, Co Donegal, but now with an address in Castletown Square, Fintona Tyrone, he denies murdering her.

Mrs. McKinney's lifeless body was pulled from Lough Erne in the early hours of April 13, 2017.

The college lecturer told the jury of eight men and four women that when Mrs. McKinney and her family returned to live in Donegal they met by chance outside a Letterkenny supermarket and their relationship developed.

"It was a normal sexual relationship," he told the court before adding that he thought Lu Na was "very nice, intelligent and shy", especially when it came to "sex".

He also claimed that Lu Na confided in him and that he "advised her to maybe seek legal advice and go to the place 'Well Woman Centre' who would take care of her".

He claimed this was because of the way he "felt she was being treated by her husband.... I just felt he wasn't treating her in a normal way in a relationship".

The lecturer also revealed that in August 2016 he contacted a "Now Doctor" out of hours service after becoming concerned about Lu Na. She'd told him she'd taken four sleeping pills. A service manager later confirmed the call, and a recording was played to the court in which Mr. McKinney agreed to bring his wife in for a check-up.

Later defence QC Martin O'Rourke suggested to the lecturer that he had nothing to back up his claims of having been in a sexual relationship with Mrs. McKinney, no emails, no text messages.

Mr. O'Rourke put it to him that he was "unable to provide anything that might show the type" of relationship he was having with Lu Na, to which he replied: "I'm sure I can find some emails."

However, he accepted that he had not shown police any email exchanges or text exchanges which might have "spoken of their relationship, explaining: "I wasn't asked."

The lecturer also accepted that he spent time in hospital being treated for psychosis and paranoia, and told doctors of "imaginary things .... people were out to get you", and that he and Lu Na only had sex on a couple of occasions and "only had intercourse as payment" for him having helped her.

However, under re-examination from prosecution QC Richard Weir, the lecturer rejected the suggestion he had not been in a relationship with Lu Na. He agreed he had been in hospital and when asked what caused it, replied: "The loss of a friend and trying to help the PSNI all I could."

Then when asked again did he "imagine having a loving sexual relationship with Lu Na?" said: "Oh no, no, no, nah."

The trial now in its sixth week continues on Wednesday