The secondary appears to range from 3.1” to 2.5” of arc from the primary, and is presently near minimum separation, according to Sky Safari.
Measures of the separation of Antares A and B have quite a scatter over time. In recent decades, the separation, currently given around 3.2", has not changed enough to be outside the measuring errors/uncertainties. Estimates of the orbital period range from 800+ years to thousands. The problem is that the PA has changed very little, and the measures show a lot of scatter within each era, so orbital estimates (they're no better than that) are very uncertain, based too much on the stars' masses and separation as projected in the line of sight, but without significant measured changes. That doesn't allow for even a good ball-park guess, beyond suggesting the period is very long. So one should read the Sky Safari numbers as indicating uncertainty because you don't get enough information to assess the pair's changing pattern, which, as mentioned, is uncertain.
Current best estimates suggest the separation is slowly decreasing. But one could make out a case for little change, or slight widening, or .....? My feeling is that Antares needs some high quality measures perhaps once each decade to better assess what's happening.
Regarding observation, with around 4.5 magnitudes brightness difference and the glare factor, it's notoriously seeing dependent. I've occasionally seen it double, though I've often seen only flare and glare from the primary without th companion. My best observation was in the late 90s with a 7-inch apo refractor, at only 100x - the secondary was obvious as a small green point of light, in very good seeing. I've always considered the colour I saw as a contrast effect with the orange/red primary.
To confuse the issue further, EJ Hartung (Astronomical Objects for Southern Telescopes, 1968) mentions that the noted double star observer WR Dawes in 1856 saw Antares B "emerge from behind the dark limb of the moon before Antares itself and noted the colour as green...".