I've had the Sims 4 for over a year now and I haven't had this issue before. I have two sims that are romantically involved, but I can't get them to interact, romantically.
I tried different options, anywhere from holding hands to woohoo, and they just stamp their feet and wave, like something is blocking them. However, I can get them to talk and have conversations, like normal.
I've already gone under Origin and repaired it twice.
Now, after installing the Get Famous mod, I can't get my sims to order from bars, either. I tell them to, but it just doesn't show up in their queue, like I never did anything.
What is going on with my game??
(Also, yes I have a lot of CC and mods, all of which are up to date)
Move your Mods folder to the Desktop and delete localthumbcache.package. Then test the game.
If it works now check for updates to your Mods and CC. Add it back a little at a time while testing until you have found all that are broken.