No he didn't have to do anything because as I said none of us know what really went on behind those doors, not you, me or anyone else.
And actually if I remember rightly the press going after her all started because she was liking and retreating negative stuff about him on Twitter.
Does that make it right, no but we all know how shallow and malicious the press can be in this country, especially towards women.
And no he doesn't owe Lisa any explanations about his wedding date, they are nothing to do with each other now.
However we don't know that he didn't tell her he was getting married but as they move in similar circles I'm sure she knew anyway.
She didn't know they were seeing each other until she saw it in the papers (and the divorce hadn't gone through then) so its hardly a stretch to assume she had to find out the actual date from the papers the same way.
Let's also not forget Lisa dealt with her husband going off with her friend/employee, the papers blaming everything on her, her looks being dragged, the loss of many of her friends, a divorce in which he fought for the dog, which was a birthday present he gave to Lisa (only to buy two new dogs once he won) and on top of that her Dad fighting cancer.
Imo he showed himself up with his behaviour as the saying goes integrity costs nothing, a statement calling off the press and making sure she heard about things privately would have made him appear a nice person, instead of someone who appeared to be doing his damdest to rub Lisa's nose in it at every opportunity, in fact rather like the person James Grant would have us believe he is.
When he made the statement that he'd put Lisa through hell he got respect from me, not informing her he was with her friend/ex employee before it went to the papers is not deserving of any respect.