While some in Armenia might still say "there are no gay Armenians", and believe it, there have been gay nightclubs in Yerevan in the past, and many of the clubs are gay friendly. While there are no laws against LBG relations in Armenia, it is still not widely accepted, and while your hosts are unlikely to say anything about it if they know, public displays of affection are still not seen. In other words, like in many parts of the world, you'll have to decide for yourself whether you want to confront this issue, or try to blend in.
That having been said, you might be surprised to find so many women holding hands as they walk, or guys arm in arm, or kissing each other hello. This simply means they're friends or relatives in most cases.