Yes, beer can definitely be aged, but it needs to be the right style of beer.
For example Pale Ales and IPAs are not beers designed for aging _ they are designed to be consumed reasonably fresh and most often will have a 12 month recommended drinking ¬ñbest before¬î date. Of course you can drink them past this date but some of the flavour and aromatics may have changed from what they were intended by the brewer.
On the other hand Strong Belgian Ales, Strong Ales, Imperial Stouts, Gueuze and Barleywines (a style of beer) can all be aged for over a decade if kept under the correct cellaring conditions.
Beers that are designed for cellaring will be more robust in flavour, body and alcohol (most often 7% plus). Most will be exceptional once aged, but they wont appeal to everyone. If you partner is more into Pale Ales then they may not be ideal _ I could be wrong though!