We have vaginal sex a lot lately and I haven't had any spotting whatsoever. The one time I had some bleeding was when my husband was in a different state and there had been absolutely no monkey business, so go figure.
I totally understand what you mean about not wanting to see any blood, even if you know that it's just from having sex. For that very reason, when I first found out I was pregnant, I found myself reluctant to have vaginal sex. I hope this isn't TMI, and that I'm not being too forward, but there are lots of things to do that won't irritate your cervix one iota - which is how we spent most of the first trimester. You may want to consider those options.
As many PPs have advised, don't do anything if you don't feel comfortable with it. DH will survive.