I agree with nightstar. You need to alert his doctor to the behaviors you witness with your husband. He sounds like he is compulsive - perhaps a bit of obsessive/compulsive disorder is at work here. It is fairly common for bipolar disorder and OCD to overlap as they are comorbid diagnosis for many people. Over spending with such frequency is associated with manic behavior. The obsession with animals is further behavior that suggest OCD and a manic state.
He sounds like he needs to get into the doctor for a medication review. He does not sound like he is stable.
Much of what rock_digger said is true. I do believe that at some point self preservation must prevail and you need to do what you must to take care of you and your children. Abuse is abuse, no excuses. It can not be tolerated from anyone. Yes, bipolar disorder seems to lend itself toward the tendency to become abusive due to mood swings and feeling at odds with the world. That can be resolved with meds and therapy so it is no excuse to be abusive.
Mood disorders are complicated. What you describe are symptoms of instability. A medication tweak or new medication is probably needed. Your husband needs to see the doctor and take care of this.
