All UTH's should be regulated by a thermostat, yours weren't "malfunctioning", they were working perfectly. There isn't anything in them to regulate their temperature... the longer they are plugged in the hotter they get. This is why thermostats are mandatory... so you can control their temperature.
As for the bulbs, are both your boyfriends house and your house supplied power from the same company? they could be producing dirty power. There are many parts of the US that have terrible power. This could be your problem. If not then you could just have really bad luck getting a bunch of lemons, but with that many I would be inclined to suspect that something else is the cause.