"I love him, therefore he is my husband."
Translation:Kocham go, dlatego jest moim mężem.
go/jego/niego are synonims, but used in different positions of sentence. "go" is unaccented , "jego" is stressed, niego is stressed too and used only and always after prepositions.
I think in this sentence You can translate either
Kocham go, dlatego (on) jest moim mężem
Kocham jego, dlatego on jest moim mężem. - you put stressed on HIM in the first part of sentence , you should put stress on HE in the second part to