I believe in loyalty (not being a fair weather friend), finding compassion and understanding for others. Looking first at what I can change in myself before critisizing others. Not betraying the personal trust put in me by others.
If I may suggest an angle on this that might make it easier to at the same time be compassionate to yourself? You should be loyal to others - but not to their pleasures. To be totally loyal we have to be committed to the best in our friends, not the worst in them. This is obvious if we have a choice between being, say loyalty to their desire for alcohol or loyal to their desire to pay the rent. That's not really worth calling loyalty - that is what Kant has in mind when he talks about servility. (Although people who want us to be servile will often label compliance with their desires "loyalty.")
It is less obvious when the virtue or vice in question is not so clear - how loyal do you have to be to someone's desire to be in control? Or to feel good about themselves at all costs? I'm thinking not very. So it always makes sense to check your principles and make sure you are treating everyone in the situation (INCLUDING YOURSELF!!!) with compassion and loyalty. It is a matter of faith, but I've gotten pretty good at this and I have only ever found 3 situations I couldn't unravel and find how to honor all my principles.
When you put those principles into an abusive situation, they become detrimental. They are the reasons not to leave, to consistently forgive, to feel empathy for the abuser and to keep what they are doing to yourself.
In my view, the problem here is not the principles - loyalty, compassion and understanding - it is that you are not treating them as moral/universal principles because you are not applying them to everyone in the situation. Specifically, you are not including YOURSELF in the scope of the principles application. (Hence the inclusion of servility in Kant's list - that is why I like his...) As well, you are not really taking accont of everyone outside the situation - who also has to deal with the "monster" you are supporting, or helping to create with your compliance.
Sorry if that comes across as harsh. I don't mean to blame you in particular, only to point out that the pattern that keeps abusers going is that abusees don't take action against them- if they did the game would have less players and end much sooner. Right? Once you recognize this you can leverage the compassion, understanding and loyalty to others to better protect yourself. You just expand the range of "others" past the abusers. You cultivate loyalty to others in a broader sense, including both yourself and unknown others. You use your principles to help define your boundaries in ways that really are good for everyone.
It also might be worth remembering that "sacrifice" means "trading the lesser good for the greater." A lot of people find they've been thinking it means: "giving up your own good for other people's reasons."
Responsability is something I've been brought up with and was one of the principles that attracted me to the group that I was with when I was attacked. It was a principle that was abused there - while some took responsibility, others took the role of pointing out everybody elses responsibilities. In the end I took too much responsibility, but it was a saving grace in helping me find my way out of the group. So I do still hold it as a pronciple, but am wary of it too.
But that group dynamic is not supporting individuals' responsibility! It is co-dependence! And that encourages selfishness in some and servility in others. Responsibility has two parts - the one being accountability and other being response-ability. When lack of (what would seem like "natural") response-ability to protect yourself on the part of the abusee meets up with lack of (again what sould seem like "natural") responsibility/accountability for their own actions on the part of the abuser(s) it is a dangerous situation for everyone. The tip off of co-dependence in practice is the lack of compassion for the victim, the "necessity" of the victim's swallowing even very large hurts, and the total denial of accountability for specific people's actions.
Every virtue has an excess and a deficiency - or a deficiency and a counterfeit. So, courage is a virtue - and having too little is cowardice. Having "too much" or the counterfeit is foolhardiness. Loyalty is a virtue - and having too little is being "a fair weather friend" but having too much/the counterfeit is servility or "blind loyalty." Compassion is a virtue - and having too little is being insensitive, and too much is being an emotional sponge - a kind of doormat. Does that make any sense?
Hope this is clear and helps! (and isn't just pedantic...)