30yr. Land Lease Revisited!i've Read A Couple

I've read a couple threads on the subject and am still confused.I recently married a Thai woman and am buying land witha house.I spoke to a lawyer here in Khon Kaen who stated that I could not file a 30yr. lease agreement with my wife because I am married to her.He said it was possible to do before we were married but it is not legal to do now.He stated a"lessor" cannot be related to a "lessee" in such a way.He suggested if I wanted a 30yr. lease,one option would be to end the marriage,file the 30yr. lease, and then remarry.This, it seems to me, would complicate the issue even more,not to mention the cost and time involved. He did draw up a paper with the heading,"Exchange Agreement". It was similar to the lease agreement I've seen, except it stated that it was solely my money that was being used for the purchase of the property.It also stated that foreigners, pertaining to me, cannot own the land.It will be in my wifes name alone,which I understand.What I don't understand,from readingother threads,some falangs married to Thai women have filed leases at their respective land offices without question.This makes me wonder how a lease such as this would hold up in a Thai court.I don't know of anyone who has used a "lease agreement" as a legal defense in court.Also if anyone is familiar with this "Exchange Agreement" I would like to hear from you.Anyone with a lawyer referral in this matter would be appreciated.