What ever you do, DO NOT BE NEGATIVE!! Positive thinking will get you out of this!! Read on:
Go away for the weekend. Make a change of scenery. Go to Disney Land or something! Or Cedar Point! The zoo, a field trip, anything different!!!!!!!
He is tired, and so are you. Your children are getting caught in the middle and it is not their fault. You both need to find better hobbies. Find adventure (even at a virtually free park like Kensington or something!). Summer is almost here. Life will change. Talk to your husband about outside activities you want to do, ESPECIALLY one that involves just the TWO of you
as well as many that involves the whole family (and if he isn't into this at first- go with the kids by yourself. Do something really great he will want to be a part of. Do some homework, be creative! I know you can do this. He will join in, and the whole family will be all-smiles!). Think Free to start. Art in the park, dinner/lunch on weekends at Kensington w/ bike rides, maybe some BBQing, fishing ,whatever. You know what your family likes- flying kites, camping, whatever. Have fun. Your family seems like it needs to get out of a nasty rut!
Work your way into happiness again. Be patient, do some good planning...Your kids will thank you for it and be better little people, just like their parents!!