He's living with his partner Camilla, an assertive aspiring young doctor who is pretty much the driving force (not to mention, main financial supporter) of their otherwise contented life together.
And even though he lives in a house bought and paid for by Camilla's wealthy father, still Jack struggles to afford an engagement ring to go with the very proposal he's just sprung on his tearfully accepting now fiancée.
Soon, Jack is reminded that Anna is someone he drunkenly hooked-up with at some concert 8 years previously - a one-night stand as it happens - and informs him that they have a seven-year-old son called Phoenix.
Camilla however soon finds out the truth when Phoenix needs to be rushed to the hospital she's working at after a nasty fall from a jungle-gym at the playground during one of their weekly visits.
Jack is devastated and attempts to explain and set things right, but ultimately understands that the right choice is actually making his son his priority and to just give the situation some time.