Just to give another angle... I've been here. I kept my last pregnancy from DH for a couple of weeks, as I wanted to find out how far along I was (v irregular periods) before bringing it up, as I've had a few very bad, very late periods that doctors have said may be very early MCs - but no way of knowing after the fact, with my irregular cycle. So I arranged an early scan which suggested I was only about 4-5wks along at that point (so I'd been about 2-3 when I first tested) and then I told DH. He was fine with this and said he was glad I'd only told him when it was definite, rather than 'just' a POAS test.
About two weeks later, I had another scan (at midwife's request) and it was clear that the pregnancy wasn't going to continue, so I had the choice of miscarrying naturally or medically. I chose the latter and DH was fully supportive at the time, but we had a massive falling out a couple of weeks later, which I think was largely down to me still being upset and hormonal, him being upset and disappointed, and not understanding that I was still suffering the hormonal effects of that pregnancy, because, after all, I was no longer pregnant, and 'it's not like I was really pregnant, after all'.
I believe that argument (which was horrible, and we're still a little shaky about it) wouldn't have happened if DH hadn't known about the pregnancy and later MC. I'd have been upset but on my own and I'm really ok with that. On that basis, if I get pregnant again then I will keep it to myself until I've had a scan that shows things are as ok as they can be. I told DH this and although he isn't fully ok with it, he also appreciates that I'm the one going through it again and again, so it's just my medical status, if you will, until there is actually a viable baby, and that there is a limit to what he can do to help, and no limit to what he could do to make it worse.
PPs have said about propping him up or saving him the heartache - it's a little of both for me, but more about me managing a medical situation that affects only me unless and until it develops into something more, and doing what is best for me, as the patient.
I wish you the best for yours, whatever you decide to do.