Yes, they can. Early in our relationship, I had quite a confrontational relationship with my husband's alter Jonathan. He didn't want me to hurt Jon like the ex-wife did. We fought a lot in the beginning. Over time he came to understand that I was not the ex-wife, and that I was on their side, that i wanted to help. Now we're good friends. Sometimes when Jon is getting mad at me about something, Jonathan will come out to help clear it all up. But he was very protective in the beginning and wouldn't put up with anything that looked vaguely like unhealthy behavior from me.