"TRUST". If you don't trust someone, do you end the relationship?

This might sound like an easy question. But I am talking about anyone here. I am talking about all levels. I am talking about a person who you have been friends with for 5 yrs and that person tells you to get away from your boyfriend, who is very verbally abusive, alcoholic, etc..Now I have finally gotten away completely...after 5 long years of struggle, back and forth. Now because he is "Christian", he wants to keep this ex-boyfriend of mine, on My Christian bikers list of rides to come this summer. So as to not close the door to him, (he is not christian, the ex) Now I have to deal with worrying over will he show up on bike rides, because he has an open invite. I do not hate my ex. That is what makes it even harder. I am trying to be Christian too, but I feel so betrayed by my friend. He tells me he is unhealthy, get away, then invites him in my circle of friends to hang out! I have lost all trust in my friend. I feel he is not considering my feelings, and my gut says move on.??