This is a Q&A forum. you have not asked a question.

Your question makes no sense, and appears to be a variety of another question you have asked numerous times.

You can't sue. That may be why he won't talk to you.

You don't have any damages to sue for. If they won't leave, call the cops. Call their employer. But lawsuits are costly and you won't recover...

IMO it is entirely reasonable for them to look to your guest for the repair costs.

She can't stop you from getting a divorce. File a divorce, serve her, and be done with it.

No one can opine based upon your conclusions alone. The judge will decide based upon all the evidence.

If you can find an attorney who will sign your pleadings, yes you can sue. You don't indicate grounds to sue in your post.

A question that starts "can I sue" is almost always answered yes. Anyone can sue anyone. The issue is whether you will win, and that is determined...

You need to contact an attorney (Rechtsenwald) in Germany.