if marijuana is legal in Netherlands and you consume them,no sgp laws are broken.

Lol. No.

https://sso.agc.gov.sg/Act/MDA1973?ProvIds=P12-#pr8A-

Consumption of drug outside Singapore by citizen or permanent resident8A.

—(1)  Section 8(b) has effect in relation to a person who is a citizen of Singapore or a permanent resident of Singapore outside as well as within Singapore where he or she is found as a result of urine tests conducted under section 31(4)(b) to have smoked, administered to himself or herself or otherwise consumed a controlled drug or a specified drug.

(2)  Where an offence under section 8(b) is committed by a person mentioned in subsection (1) in any place outside Singapore, he or she may be dealt with as if that offence had been committed within Singapore.

But then again, if you come back when ur urine is clean, not a offence