My Dh is away at least half the year every year, sometimes in 6 month blocks (when overseas) sometimes in 3week-2month blocks throughout the year. it's been part of our relationship from day one so I haven't had much say in the matter.
I've found it a lot harder since having kids though, because you get no downtime (well you will with a toddler, but with a toddler and 3mo I'm basically busy 5am-11pm each day).
Make dates with friends you don't catch up with regularly, go for walks, chat online to people. You really need to keep up the adult communication otherwise you'll go insane.
I always write a list of things to do when Dh is away, like painting, sewing, house reno (that he usually doesn't know about til he gets back

) I've also found that the time he's home everything kind of stops - I guess because he's away so much we try to make the most of every minute he's here. Which means the house is a mess, nothing else gets done etc.
Make sure you have bestmates on your cellphone or something so hubby can call you and Alex once in a while (not everyday (well I don't think its necessary anyway) as it makes time drag).
The hardest parts - not having muscles around the house so having to ask other people to help, having to pick up all the slack, no sleepins, kids acting up each time he leaves (but DS is getting a lot better and has only cried once this time), getting snippy at each other because you get so used to your own space its hard to adjust again... but it also means you get a wee honeymoon period every few weeks
I don't think we could do the 'normal' couple thing where he had a 9-5 and was home all the time. I do like this lifestyle more, but its hard work for both partners which your DH needs to remember (as DH's quite often forget its hard for the wife too).