Mistress/2nd Wife Seeking Help and Advise

Okay, I have several questions so I started this thread. I'll just make my description brief:

My BF is already separated from his wife and in the process of moving out. I am not the reason of their separation. The wife does not know about me.

Here are my questions:

1. if they are already living away from each other can she still file for concubinage?

2. If they have an express/written agreement that he can live with someone else, will it be enough to dismiss a case of concubinage (or any other complaint)? Will verbal agreement be enough?

3. If they didn't have an agreement and I have a child with my BF whose last name shall bear my BF's, trust that this is not a ground for any complaint. Kindly confirm.

4. If she proves that her husband lives with me, BUT I can claim that we are just sharing the room/apartment for expenses, does this have a stand in court? I've already lived with some of my guy friends and never had any sort of sexual relationships with them. We were just cohabiting for the sake of sharing expenses and we're friends. Since I've done that before and I have so many witnesses (my guy friend's wife included) that it was solely friendship, do we have a stand?

5. If we are seen having PDA in public, or he kisses me in public and there is a witness, can this be used against us?

We want to file for annulment but our grounds are not that feasible. i'd like to hear some of your side before I actually go to a lawyer. I know that if you have the money, it's always possible to get annulled...

1.Without annulment, Yes.
2.No.
3.The child is the strongest evidence for his infidelity.
4.You can use that as an excuse. but weak.
5.That can be used to counter your alibi that you are just friend and just sharing the house and expenses.
6.Get a lawyer. The advices you will get from here is just based on details you have provided. If you have a lawyer he/she can study your situation more clearly.