Depends on your definition.
If you mean a person you can invite over and call up whenever then you can have as many of them as you want at the same time.
If however you mean a proper "romantic love interest and the one I love", not in the base game as far as I'm aware.
That said, one of the biggest mods for this game is the Lexville mod and while I haven't actually given it a try yet, it does say that it expanded upon romance features like so:
"Expanded options for relationships, like getting your lover's home key, having them move in with you, joining them in bed when they're asleep"
Mod here:
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