***NOT AN ATTORNEY***
1.) Yes, it can affect you in that if the suit is successful, your wife's need to pay the judgement will put a strain on your family's financial resources if you are still together. I don't know whether or not the plaintiff can come after marital assets, though. My guess is that to a limited degree, they can.
2.) Awards vary greatly. Anywhere from several hundred to several millions of dollars. All sorts of factors are taken into account. Length of time the affair took, how aggressively did the paramour pursue the plaintiff's spouse, what was the state of the marriage prior to the alienation, etc.
3.) If you and your wife are working on repairing the marriage, then her affections haven't been completely alienated. You could file a similar suit, however, it might not go vary far for that reason.
FWIW, these kinds of cases take a fair amount of money to pursue. They also take a fair amount of time to see them to completion, during which time, everyone's private life and sexual history can get carted out into open court and become a matter of record. In addition, if there's not much financial gain, generally speaking, many attorneys won't pursue the case but try to force a settlement, if they agree to take it at all.
My personal opinion is that if the injured party has children, those financial resources are better off being put into the service of the children. If they don't have children and they aren't suing a millionaire, why waste their money getting revenge? Why not use it to go somewhere, do something, or get something that makes them happy?