The 36-year-old star has a daughter - Gracie, seven - from her time with David Thewlis and revealed she thinks her newer relationship of two years finds a balance between the hardships and ''glorious'' times.
Speaking to the Sunday Times newspaper's Style magazine, she said: ''Well, I am the mother of a child that isn't his, and of course the situation can be problematic.
''But he has his own place in Notting Hill that he can go to and it is what it is. All you can ever do is do your best.
''Sometimes it is not plain sailing and at other times it is glorious, and I think that is what a relationship is.''
The 'Look of Love' actress lives opposite her ex-boyfriend, and it is part of an attempt to give her daughter the most normal upbringing she can.
She added: ''I wanted neighbours, I wanted a sense of community. Being from a relatively small town, and spending my holidays in Ireland, where my dad is from, I find it more homely.''