At 5w4d I had a cyst rupture, and saw the gestational sac and the yolk sac. A week later, at 6w4d, we had a heartbeat of 138.
Try not to over-think everything until you get to be seven-eight weeks with no heartbeat. Why would he be "covering his ass," I don't even understand why that would be a factor in this, he can't cause you to have a miscarriage.
Yes, it may happen, we all have that chance. (My loss was discovered at 12 weeks, after I saw a heartbeat numerous times.) But as of right now, you're measuring pretty-much on track. So relax, and don't spend the rest of the week in fear. Good luck to you.