It could mean he is not interested in getting married again or it could mean he doesn't want to spend the money/put in the time to go through the whole legal process. (Men can be lazy in matters such as planning a wedding or initiating a divorce)
Recently there was a study that determined (women initiate divorce 66% of the time!) That's 2/3rds!
Apparently men are not only hesistant about entering into marriage they're also hesistant about filing for divorce.
I've personally known couples who have lived separate lives for over 20 years without legally becoming divorced.
The bottom line is if he "wanted to get married" again he would divorce his wife. However I must admit most people are in no hurry to re-marry after going through a divorce. It's pretty much a "been there, done that" kind of thing. It's even more difficult to consider if there was a steep financial price to pay, heavy drama during the split, or kids being turned against a parent. "Once bitten, Twice shy".