I'm sorry for your previous loss.
With our second loss everything developed as normal (betas and everything) until about 7 weeks. We had a u/s and saw a HB at 7w5d though it was a little slower than normal and I was measuring a little behind despite charting. My doctor reassured me and we told our immediate families. At 11 weeks I started spotting and we discovered that our baby had passed just a few days after the u/s.
In my opinion, there really isn't a "safe" time because things can happen well into the second and third trimesters or even at birth. Tell the people you care about when you are ready and just hope for the best. I wouldn't tell anyone you wouldn't want to un-tell if something were to happen though, at least for now.