remove restrictions - edit 'riv_rel - overall settings.cfg' (generated when you play) to set consanguinity_limit = 1 and direct_rels_are_incestuous = False.

add restrictions - ensure global incest is switched off in WW (this is the default option) and that no sims have the incest trait.

WW - you can't remove romance restrictions with WW while adding them with my mod (it won't crash the game if you do this accidentally dw).

It won't mess up your save (it's sizeable, but most of it works with its own framework, though there are some injections), but there are a couple of known conflicts:

computer add-on for the 'Research on riv-rel.sim.' help menu, which lets you choose a particular command / feature and get a notification with an explanation.

traits (optional addon): tutorial is here, it can be skipped.

sims that are directly related (great-.-great-grandparents/children).

sims that are second cousins (share a pair of great-grandparents), or at least as closely related.

by default, romance will be prevented between.

if your save number changes, just re-enter this command.

back up relations by opening the cheat console and entering 'riv_auto xyz' - replace xyz by a keyword you want to use for this save, and it'll handle everything for you.

using the cheat console and entering, e.g., 'riv_rel Bob Pancakes Iggy Pancakes'.

using the friendly interaction 'Ask if Sim is related', or.

gedcom files to keep genealogical information even if sims are culled. This mod in one long sentence: riv_rel calculates and puts the exact bio/in-law relation between two sims into words, adds a friendly interaction to ask a sim exactly what their relation to your sim is, adds a bunch of console commands (enter riv_help to list this in game), adds options for additional incest prevention, and you can create external.

First love mod sims 4