I joined a group fairly recently (about 4 months ago) however my reception was, if anything, quite good. I think it helped that they had gone through a few players that caused some problems and were releived that I wasn't a complete jerk. Even so it wasn't a meeting of long lost brothers to begin with. I find gaming groups to usually be the least judgmental but are usually reserved in their opinions and slow to open up. I found that inserting my character into the group in the least disruptive way possible was key to acceptance. Each player had spent time carving out their niche in the party and for me to barge in and take over someone's modus operandi would be a recipe for emnity. Instead I watched and helped out where I could. If the party had a weakness or an unasigned role, I took it if I could fit it into my character's persona. I looked at what the other players were trying to do with their characters and made efforts to try to augment it. The charging Cavalier in our party often needed a lowly guard type obstacle cleared out of the way for a charge on the big baddy, so I tried clearing the way. The Sorcerer needed someone to act as a blocker while he got his improved invisibility off so I archerized the hell out of stuff and stayed close to him. I think my OOC comments helped too as I am a closet wise ass that only comes out in roleplaying.
As for outing yourself as a role player, there's one in every one of us. For instance your boyfriend didn't turn out to be who you thought he was. He was a role player. He just didn't use dice...or a frontal cortex.