I haven't found another person with this glitch... so far.

[Mooncalf]

My guy's wife died in a fire.

When I asked somebody new to be my fiance, my sim vanished. After using ResetSim, I can no longer actively interact with the new person.

My limited knowledge tells me that something is bugging, when I try to have a relationship with anyone who is or has been in a relation that is "going steady" or better.

[severedsolo]

Are you using any core Mods? There was a problem with people running outdated versions of AwesomeMod that caused Interactions to disappear.

[mangaroo]

Remember, any problem, issue, or error in your game really belongs in the Help section. Discussion is for "how do I do this?" type questions, not "my game is busted!"

Click on the Help dropdown at the top of the page, then choose Sims 3, and see the FAQs there. Make sure that you actually do what the FAQs say, not just read them, if they're relevant to your issue! If you still have problems after working through the FAQs, please post a new thread in the Help forum. You'll find a link on the main page of the Help FAQ index.

To avoid posting in the wrong section, please read the Discussion Guidelines: http://www.modthesims.info/announcement.php?f=558&announcementid=141

Good luck!