sprman24, hi and welcome.
I can venture to say I understand your dilemma from both sides. Here's what I've come to find: being in a relationship with someone who's abusive, or A, or untreated mental illness or whatever IS isolating. It doesn't have so much to do with you isolating yourself on purpose: it's just what happens naturally.
I've been on both sides of the equation: from the perspective of friends on the outside looking in, it's hard. I had a friend one time whom I invited to stay with me after her boyfriend knocked her to the floor during an argument. Cops were called, hospital. She went back to him--wasn't ready to leave--which we all know happens with DV, of course. But as a friend it was awkward: no I didn't think anything negative of HER for going through it all, but as a friend how was I supposed to just hang with them again? Sit there laughing at his jokes or whatever? Go over and say hi when I saw him in the grocery store? Finally I had to tell her I would always be there for HER but I couldn't pretend I hadn't seen her bruises. And she got angry at me for a while. She's in a better place now and he's history, thank god.
And then from the other side: as the partner of someone who's an alcoholic, I've felt the same hesitancy to be totally honest with friends about it. Because I mean, really, unless they're also in denial, I knew they'd be like, "Um--you're still there why?" And then hanging out was weird: if we were all out seeing a concert and then they saw him drink one beer and then an hour later be completely out of control, of course they were going to be "busy" the next time I put out an invitation. And then things like: I couldn't have the writing group at my house, because what if it fell on a booze-fest day?
It does help to make a network of friends through Al-Anon or whatever who understand what you're going through.