I have various contacts and friends who know the Hogans.... so I have gotten alot of 2nd, 3rd, and 4th hand information about their marriage. Here's a handful of the rumors I've heard.
1) Ironically enough, the "Hogan Knows Best" reality show is actually one of reasons that their marriage became very tense in the first place. I guess being in front of cameras all day 5 days a week can make any situation tense.
2) Moving to Miami put a big strain on their marriage. Hulk hated living in Miami and plans to move back to Tampa permanantly now that they are seperated.
3) I've heard Linda Hogan described by numerous people as being "two faced" or "bi polar." Apparently the Linda that we see on "Hogan Knows Best" is far from the real thing.
As stated before, this is all 2nd, 3rd, and 4th hand info but it originates from reliable sources.