These icons () show footnotes as tooltips... for some browsers.
Alabama "owns" I-59 in that all its 3-digit interstates are entirely within the same state, even though I-59 passes out of state.
If the woman you're dating is not fascinated by this, leave her and find someone who is :-)
I-359 Alabama (link)
2.30 miles ; from I-20/59 north into Tuscaloosa (home of the Crimson Tide). Opened between 1976 and 1981. Proposed in 1971 or earlier.
I-459 Alabama (link)
32.80 miles ; serving Birmingham, it loops I-59 to the south. Interstate 459 was originally planned as "Interstate 59B," but this designation was changed to 459 before the highway was built.  It was completed in 1984. 
Most of Interstate 459, except a short section near I-20/59, was built as a six-lane bypass with a grass median. In the early 1990s, Alabama paved over the median, not to add lanes, but merely leave wider left-hand shoulders and the Jersey barrier. This implies that the state plans, once it widens the bridges, to make I-459 eight lanes.  
The plans for I-459 date back at least 35 years. Hearings were held in May 1961, September 1966, and October 1968 to resolve local objections to routing. The original plan was a complete loop around Birmingham; in its stead, business and "white flight" have left the city for points along the bypass. Apparently county and surrounding city funds were in place for the north loop, but Birmingham itself, saddled with some ethical problems, could not come up with its share. 
Northern Beltline planned to complement I-459
The mirror image of I-459, a 51-mile northern Birmingham bypass, is one of the ISTEA/NHS "High Priority Corridors."  As of late 2001, right-of-way was being purchased in this area.  However, it's not definite whether this road will also be signed I-459. 
I-759 Alabama (link)
4.50 miles ; Short spur in Gadsden from I-59 to Rainbow Drive. Interstate 759 opened between 1985 and 1989. In 1999, the Alabama legislature designated I-759 the Joe Ford Expressway.
The presence of I-359 (Tuscaloosa) and I-759 (Gadsden) would imply that Alabama once planned an Interstate 559, perhaps in Birmingham; however, ALDOT says there's no such thing as I-559, former, future, or secret.
Two extensions planned
Plans are afoot to extend Interstate 759 in both directions: northward/westward to US 431 west of Attalla ; and eastward to George Wallace Drive, eventually to US 431/278.  This would change the role of Interstate 759 from an I-59 spur to a US 431 bypass.
In March 2004, the Gadsden-Etowah Metropolitan Planning Organization (MPO) formally endorsed the I-759 West proposal, adding it to the 2025 long-range plan. The extension, already proposed in 1990, would relieve congestion caused by commercial and industrial growth. Cost might be around $70 million.