So is 1.10 the last version where interfaith marriage was possible? I've sort of lost interest for a while due to this standing issue (and others i came across during my mod work), but i may roll back to an earlier version (not Steam, so it is possible for me).
No, it was version before, it was 1.092 or something like that. The patch that changed things, was the patch which came with TOG (1.10).