Can a lawyer represent someone if consulted by the other party prior to current events?

That is a big no-no on the part of the attorney.  Attorneys are supposed to perform conflict checks before consulting with potential clients, and if they had, it would have shown that he talked with you about it already.  Representing her on the same or similar matter that you consulted him about is a violation of the Rules of Professional Conduct.  You should talk with your attorney about advising the other attorney that he needs to withdraw from representing your spouse, and if not, them you may want report him to your state bar.   In fact, you may want to report him whether he withdraws or not.  If he is not performing conflict checks before taking on new clients, you might be doing future potential clients a favor by making sure he is re-educated on that requirement.  Talk to your attorney about it.