Probation is tasked with trying to keep probationers from reoffending. To do that they set down conditions which are designed to remove triggers and stressors from the probationer's life so that he can stay out of trouble while he learns better self-control and coping skills. It is typical that a probationer will be forbidden from seeing complainants on cases, and that, unfortunately, includes family members who have pressed charges against him.
Probation has the power to split up families like this, and there isn't very much that can be done about it, as your husband's fate is in probation's hands. If he violates the terms of his probation, he will not be allowed to remain at liberty.
If he wishes to be in contact with you and feels this condition is unfair, he can take the matter up with his probation officer. If his PO won't budge, he can speak to his or her supervisor. Ultimately, if he wants to, he can contact his lawyer and get a hearing before the judge on this matter.
A judge has the power to overrule probation. Judges are very conservative when it comes to that, however. They generally will only intercede on a matter like this if probation is being arbitrary and capricious. Here, where you have called the police more than once against your husband for domestic violence matters, probation would appear to have a good reason to keep you apart. I can't guarantee that the judge would refuse to let you live together while your husband completes his probation, but I think it's a pretty safe bet that he would let the order stand.
So to recap, he can get a hearing with the judge to see if the judge would overrule probation's requirements. In my experience, it will probably not succeed at this point. Meanwhile, he can go to family court to work out some kind of way to see and provide for his children without violating the Federal order.