She would not foreit her rights to the home by leaving. She is entitled to 1/2 the marital assets unless she signs saying that she is giving that up. My suggestion, have her file for divorce from bed and board and have him leave the home.
From the home site:
“What is divorce from bed and board?
Divorce from bed and board is an antiquated statute and concept, but it still has its place in family law. It is, essentially, a judicially-sanctioned separation. In order for a spouse to prevail in a divorce from bed and board action, he or she must establish that the other spouse has committed one of the following fault grounds: 1. Abandonment. ( i.e. willfully leaving the marriage without just cause and without the consent of the other spouse) 2. Maliciously turning the other spouse out of doors. 3. Cruel or barbarous treatment that endangers the life of the other. 4. Indignities that render the other spouse’s condition intolerable and life burdensome. 5. Excessive use of alcohol or drugs so as to render the condition of the other spouse intolerable and the life of that spouse burdensome. 6. Adultery. If the court finds that at least one of these factors exists and that the marriage has deteriorated so badly that the only remedy is to force one spouse to leave, it will do so by granting a divorce from bed and board. If the court awards custody of the children to one spouse, a corresponding child support award may include possession of the marital home. The court might even order transfer of title to real property as part of an alimony or child support award. It is very important to note, though, that forcing a spouse to leave the marital home is quite drastic and courts are reluctant to do so unless the evidence strongly supports that course of action. It thus makes sense to consider seeking possession or ownership of the marital home in conjunction with an action for divorce from bed and board, alimony, postseparation support, and/or child support. At the very least, such a claim forces the other spouse to deal with the situation and may lead to expedited resolution of some separation issues.”
If you believe that she is in immediate danger then by all means have her leave, with the children, long enough to file for this. After this is granted she could go back to the home, change the locks and call the police if he shows up. The separation agreement is just that, an agreement. They will be legally separated the day that they start living separate and apart and do not have to have an agreement for that to be official. She can possibly use the affair to gain custody and alimony, if it’s an option. Even though she condoned the fault previously by forgiving him and staying in the marriage, she could use it if she has proof that he has started cheating again.
Having been in a similar situation before myself, I would suggest to her that she listen to her gut instincts. If she thinks he’s cheating again, he probably is. Being bipolar has nothing to do with whether or not you are faithful to your spouse. In my opinion, there is no excuse that is valid for being unfaithful, with the possible exception of total amnesia.
Find out whatever she can about his actions, cell phone records, credit card receipts, have him followed for at least 2 weeks. Keep records of everything. Record phone conversations if it’s possible. Tuck anything she finds away for later use. It may never be needed, but in my opinion it’s better to have it an not need it than to need it and not have it. Be ready to know the truth if there is something to find and if she doesn’t find anything, be thankful and tell her to make up his mind about staying in her marriage.