Teen dating rules

Our 16 year old has a girlfriend that of course he wants to spend all of his time with. Due to some issues at his girlfriend’s house (DV type stuff) we do not allow him at her house so they hang out at ours. We allow them to hang out in his room, door open. Recently, my 12 and 7 year old sons have made complaints that they are tired of her always being around/feel uncomfortable when she’s here.

How the heck do I navigate this so that my teen gets to hang out with his girlfriend, but my other kids are comfortable in their home?