This Valentine's Day it's easy to become entangled in an affair. For instance, Georgetown Park is having a free one Sunday, with big-band jazz 1 to 3 and a professional ballroom dance couple offering instruction in dancing a la Fred and Ginger. Dance contest at 2. Call 342-8190.

There are love songs: at the Portrait Gallery Kathie and Terrence Gaus-Woollen sing romantic tunes from America's past, Friday at 7:30, Saturday and Sunday at 1:30. Free, but reservations requested at 357-2920 (357-2137 weekends). And the University of Maryland Faculty Vocal Ensemble croons on Sunday evening, starting at 8:15 in Tawes Recital Hall at College Park. Admission is $5 ($3 for students and those over 60), Call 454-6669.

The Woodrow Wilson House trots out the love letters that president penned to Edith Bolling Galt for a reading Sunday at 3. Tours of the house begin at noon, at 2340 S Street NW. Admission $2 ($1 for students and those 60 and over). Reservations suggested: 673-5517.

And cut out a Victorion romance for yourself: the Surratt House & Tavern holds demonstrations Saturday and Sunday, noon to 4, on how to make Victorian valentines, and there are 50 authentic ones on display as well. Admission is $1 (50 cents for students, 75 cents for 60 those and over) at 9110 Brandywine Road in Clinton. Call 868-1121.