Dress up. Get them in this order if you cannot buy all of them. This first list is for you.
Shorts or bib shorts. Bib shorts can be more comfortable, but the loo may be more difficult. Avoid white.
Jersey. All shapes and sizes. Avoid all yellow or red polka dots on white -- in my experience they tend to attract way too much attention. We all know they are not necessarily mimicking Tour de France stuff, but it still draws a lot of eyes.
Cycling shoes with cleats, and matching pedals. Ask the bike shop.
Base layer wear. Cycling specific gear not necessary, but wear something wicking. No cotton.
Raincoats or cycling outerwear, especially the sturdy ones that won't rip around your ass when you ride. Season's changing and you can expect rain at a moment's notice.
Tools. This list is mainly for your bike.
Bottle and cage. If you ride for exercise you must drink. Cycling bottles, or bidons, is the best way to drink.
Puncture repair kits and mini/folding pumps, and ideally a saddle bag to keep the kit inside.
Headlights that let you actually see the road ahead and not just an indicator for the oncoming sleeping truckers that you are a living being.
Basic repair tools, like allen keys, chain pin drivers
CO2 pump, if you don't want to jack off to your bike after a flat.
Pannier rack if you carry stuff
Umbrella holder if you are living in Japan and don't mind looking like a granny, if you don't want to get wet. (one hand cycling is illegal here and this is the way to circumvent it)
Mudguards. If you want to keep your bike light, use Ass Savers (brand).
Basic or advanced bike computers or GPS units, like Garmin Edge series, if you want to improve your performance and start training. At this point you can consider for yourself what you need.
For your SO, get location sharing apps like Glympse, or pay for Strava Premium and use Beacon to share your location as you ride.