While there is speculation that neutering them later in life makes them less susceptible to hormonal imbalance and certain cancers and joint problems, it is not significant enough that you should delay neutering your dogs now. And if that sentence confused you, I mean: neuter them now. 18-24 months is probably an optimal time to get them neutered in terms of growth hormones and such, but the only time I would really recommend such late neutering is with performance dogs who really really need their bodies at its optimum.

Question: How does your boyfriend treat your dogs? Is he sort of passive and lets the dogs run wild, or does he lay down the rules?

From your post, it sounds like you're the primary caretaker of the dogs and so they understand that you lay down the rules. However, once your presence is gone, the household is up for grabs. If there are toys and food around and you're not there to supervise, your dogs may very well fight. Remember: dominance is about controlling resources. It is a social construct to eliminate tension and aggression. Dominance is healthy, but it is not necessarily interlinked with every act of aggression. Dominance is used to prevent it. So if your dogs are fighting, find out *why* they are fighting. It may not be real dominance. Oftentimes, it has to do with a toy or food or a bed or some other type of resource. If both dogs want a resource and there is no higher authority to dole out who can/can't have it, a fight could ensue. For this reason, pick up all toys and treats in your house and keep them in a bin. Only give them out when you can supervise the dogs. It is also an excellent opportunity to begin "Nothing In Life Is Free" or NILIF: http://k9deb.com/nilif.htm

Choose your rules carefully and stick to your guns. At this age, the dogs are adolescents. Remember when you were an adolescent? Remember your parents going insane? That is going to be you for the next couple months, so choose your rules and stick to them.

Also, until you can leave home completely confident that your dogs won't fight, crate or muzzle them. Better safe than sorry. I know many many folks whose dogs fought when they were away, and they came back to a dead or almost dying dog.