Can preseed be used overnight?

I'm having a lack of EWCM and am a bit dry. I think this may be why I haven't gotten a BFP yet. 
My husband gets up VERY early and likes having sex in the morning. I don't tell him when I'm ovulating because I find that it causes a bit more stress ( this is our 9th month TTC) anyway long story short would it be ok to leave the preseed in overnight so we're ready to go when he gets up?!