So far as I can remember:

Right hand/heart inwards: committed/bethrothed/engaged
Right hand/heart outwards: looking for love
Left hand/heart inwards: married
Left hand/heart outwards: widowed

I wear mine (rose gold, craftman made in Spiddal) right hand/heart inwards to prevent wear and tear against my 9 carat wedding ring which already occupied my left hand well before I bought my Claddagh about 17 years ago!

Best regards,

mooman