It's been my experience that BPD and NPD people want to (have to) be in control of their partners. When they feel like they're loosing that they will retaliate in some manner.
I don't know if this will be of any use to anyone but just wanted to list some methods I've seen over time. I honestly didn't realize this for a long time, mostly because relatively normal people just don't think this way. Here goes:1. Talking behind your back after an argument, twisting facts and using the kids as pawns, trying to turn them against you.
2. Outbursts of rage, this is a very strong control manuever in that all of us want our homelife to be peaceful, a safe haven from the world. When you know you have a loose cannon at home you often make concessions just to avoid the explosions that inevitably will occur.
3. Ambush, that is jumping you with something you discussed in confidence in front of other family members such as kids, lesson learned here is don't discuss anything sensitive with them.
4. Running up credit card bills and spending your $$$ with little concern for the consequences. Yes, this can be a control move as well. Best thing I've found to do here is don't share any credit cards (e.g., get your name off of all of their cards).
5. Having kids in the 1st place, this undoubtedly locks you in to long term commitments one way or another.
6. Continuous character insults when there is the most minor disagreement. This can lower your self esteem, even with the strong, over time if you are not watchful.
7. Shirking routine responsibilities, not pulling their weight in supporting your home. This probably goes without saying but it becomes more pronounced during times of conflict.
Of course we have something to do with all this too but if you're unaware of the mindset you are dealling with most normal people can fall victim to any of these maneuvers.
An obvious answer is to just get the hell out of there. If you realize what's going on early it's much easier to do but as time passes by it in effect becomes more difficult for many reasons such as kids, finances, inertia, practical considerations, etc.
The longer you stay the more you'll pay in every way, up to a point. At some point in a marriage it's a very close call as to which option (stay or leave) will cause the least amount of damage, particularly if you're able to find a separate peace and for the most part go your own way.
This is what I've learned up to this point in time, however the story is not over yet and I'm still open to something new, some new revelation.