
Hi,
I'm no expert but have had years of doggy experience and there will be others that offer different opinions to me ;)
First up, have you had him vet checked to see that his health is ok? Him going mad when a bitch is in season is nothing unusual, some dogs are very keen, and afterall, his prime objective in life is to reproduce :P I'm not surprised that he was so restless living with 6, presumably unspayed bitches.
You say that he messes periodically, this sounds like either a resentment thing of perhaps a slight change in routine that you have not noticed, but that he has picked up on. I would completely forget the crate idea as he shows such distress towards it.
I would suggest that you will have to go back to basics with him and treat him as if he were a puppy. Take him out into the garden often, always go with him and when he does his business, give it a word, like wee wee or poos and then praise him and give him a treat. He should then associate this word with what you want him to do.
HTH