In the summer of 2014 I got my licence and bought a CBR500R; took delivery the Friday before the Labour Day weekend.
Two months later I got bored of the 500 and bought a used Fazer 800. Not nearly so quick to bore of this one -- I've had it for 2-1/2 years -- I've still got it and ride it but...
...I sold another toy (a car) with the intent of purchasing another new bike, this time a Tuono Factory. I don't see myself ever getting "bored" of this machine.
I do, however, see myself getting bored with and weary of public roads -- especially the straight-arrow roads around here -- and what we're allowed to do on them, of other drivers and traffic in general, construction etc. Sitting on this near-race bike in stop-n-go traffic seems like a crime against something or another. TBH, it wouldn't make much difference if I was on the 500 or an R3; clogged traffic, straight roads, humourless police and lop-sided enforcement is going to dampen your spirit no matter what. I hate deciding to leave the bike at home on a nice, sunny day because I simply do not want to wait in so much traffic and construction on the way home.
OP, are you sure you're getting bored of the bike(s) or is it a general, more overarching malaise that's got you?