Exercise, that mean old word...I wish losing weight was just exercise..lol got that one down.
If I may make a suggestion, there is no magic pill for motivation, but there is that promise you made to yourself to be fit for 40. You MUST articulate all the joints in your body everyday, how you do it is up to you, but in order to take care of those kids, to pick them up without throwing out your back, to run up and down those stairs without getting winded, your going to HAVE TO get and stay in shape.
How? make an appointment with yourself just as you would make a date with someone. You wouldn't blow them off, why blow off a date with yourself? Personally, I can't have breakfast till I get somekind of work out in. You gals with little ones have to set the clock an hour earlier and just get up and do it. You'll get use to it and even look forward to it - I Promise.