I am with Happy and Lady , sorry. (I too think you moved in together too soon. Can you keep your finances separate for a while until marriage?
I am glad for you that you got out of bad relationships, well done.
But, ummm, you might be jumping the gun in thinking a three month relationship is your Holy Grail. It is taking a Lot for granted and at face value, iyswim.
The real him can be kept hidden. Six months as said above is true...my experience was two years (!). The fact your family/friends think he is great is not really something you should bank on either. The one I was with performed to the audience--but privately: gaslighting, EA, beginning physical abuse: nasty.
There are milestones that can reveal the truth as you go along no matter how much time has passed. I am thinking about the men who are great up until the woman gets pregnant, then goes crackers at the change of lifestyle (or the Maddona/Whore thing). Or serious illness: my cousin's dh divorced her because of her medical diagnosis (MS), yes, really.
I say to enjoy the present. But be careful not to develop expectations for the future.
And...
And please, when your gut pings that something doesn't add up, please don't dismiss it because he was so great before (or he is just tired/drunk/stressed etc etc).