The thing that gets my husband motivated to exercise is letting him see how much I exercise. If I'm going for a run outside while he's sitting on the couch, it's like an inadvertent guilt trip from me and most of the time he'll actually volunteer to tag along, though sometimes I use a little force.
I cannot post my ONE idea here ... but seriously it does work! ;-)
My kids get my husband going more than I ever could. They ask him to go to the park and play baseball or lacrosse and he always says yes. Though not a focused gym program, this is great exercise and he enjoys doing it.
If he likes dogs: get a Weimaraner or Jack Russell Terrier (and check the rescues first :-).
Maybe you just have to find an activity he likes to do that he hasn't done in awhile. Or join a sports team.
As Karin suggests, have you ever tried keeping up with a Jack Russell terrier? Probably not. There is no way that you will ever motivate your spouse. The motivation comes from inside. She/he can watch you as you get ready for your workout, but unless the light comes on inside it will be short-lived. Just ask your spouse what is important.
Exercise yourself!! It worked at my house and with my Clients!
Join a recreational sports team together. Choose a sport that requires running, such as soccer.
When you go somewhere together, just park in the back of the parking lots! =) It's a start!
I actually train my spouse. However, this is at her request and doesn't always (more like rarely) work well with couples. I have been hired by other trainers to train with their spouses and family members though. If you go that route: show them how to pick a good one, don't impose on their trainer (unless absolutely necessary) and be supportive, they need encouragement with impartiality.
I also train my girlfriend(we have been dating for years and I recently was certified). I am using a point system promising her a shopping spree for a certain number of points earned. I use process goals(# of workouts, or healthy food sacrifices) and product goals(%body fat reduction, lbs overall weight lost). She is seeing good results after a month or so of training her coworkers are noticing although her overall weight hasn't changed much she has lost at least 6 pounds of body fat though
No problem, we both cycle and weight train together. I'd say pick something that you both enjoy and can do together i.e. power walks, gardening together, co-ed softball, ect.