I really love Joan, but I will say I was alarmed to find she'd turned her back on so much of her personal life. But, extending from that, I'm not comfortable with equating that to being in an abusive relationship since -- as you even said -- Sherlock in fact supports her relationship with her family (and -- in arranging a sub so she could go meet Em without qualm or theatrics -- her friends). So I'm going with she's in transition and swept up in all these big changes she's found herself in the middle of/compelled to make, and is finding a balance.