Dear Dáithí: I'm tempted by my girlfriend's flirty cousin — Help!

"Don't forget - the grass is always greener, but its twice as hard to cut!"

Dáithí Ó Sé. Pic: Domnick Walsh

Dear Dáithí,  

I'm 35 and live with my girlfriend, who's also 35.  We don't have children, we've been with each other three years, we rent an apartment together, all the bills are split 50/50.