Once he landed the role on Shameless, McAvoy began a relationship with his on screen love interest Anne-Marie Duff, who is nine years older than him. When they first started going out they allegedly remained very tight lipped about their relationship.
They got married when he was 27 and she was 36 on 18th October 2006.
When asked about his relationship and fame, he said; 'We keep our noses clean and keep our stuff private. We don't have affairs, we don't turn up to parties, we don't fall out of places drunk. We're not that interesting. I don't wear a dress where you can see my knickers when I'm getting out of a taxi. Do you know what I mean? I find all that weird.' (IMDB)
When McAvoy was asked if his celebrity status made it harder to be faithful, he replied; 'I have a wife, so I'm monogamous. And my heart also belongs to my son and my grandparents. When it comes to my friends, I'm no longer quite as generous with my love. That's to do with age. I realised that my energy does have boundaries.' (IMDB)
They had their first child on 5th June 2010, called Brendan; however he does not discuss his son in interviews. Brendan was named after Duff's father and they both chose not to know the sex of the baby until she gave birth to him.
The family used to refer to themselves as the 'McAvoyeurs'.
Sadly, on 13th May 2016- the couple announced their decision to get a divorce.
Source: Wikipedia and IMDB.