How to stop dog marking in house?

i know regulars often remember old questions...so im the girl who wanted (and failed) to convince her boyfriend to castrate his dog so... lucky me...i have to stop the dog from marking in the house. do i just apply the same principles as with housetraining - interrupt with a sharp "NO"? he was ... show more i know regulars often remember old questions...so im the girl who wanted (and failed) to convince her boyfriend to castrate his dog

so... lucky me...i have to stop the dog from marking in the house. do i just apply the same principles as with housetraining - interrupt with a sharp "NO"? he was completely houstrained but now hes coming up to one year old and i guess the testosterone has kicked in big time and hes marking his territory

if i can;t manage to train him myself then he becomes an outside dog...and although the weather is warm here i dont want that to happen

thanks!
and please...dont tell me he should be fixed, i know!! i want to but i cant as its not my dog =(
Update:
I have moved from england to mexico to be with this man so packing up and leaving isnt an option!!
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