My boyfriend has herpes simplex 1, how much at risk am i of contracting it?

Tell him...: ...To have his doctor prescribe an antiviral (valtrex, famvir, (famciclovir) etc.) and make sure he takes it diligently. That will reduce your risk by at least 50%. Don't kiss him when he has a fever blister, or even when he thinks he might be developing one. That will bring your risk down to 20% or less. Until a vaccine comes out, that's about the best you can do.