What is your idea of how a RV will be used?
Do you want to travel? Then with the rental, plan a short trip to see some places of interest to both of you. The RV replaces the motel room you would use on a road trip.
Do you want to go to a campground and vegetate? Someone can spot a rental for you at a site, or you might consider cabin camping, or you can drive a motorhome rental to someplace close enough that the trip is not boring.
My wife was never into going out to the lake to sit around. She liked road trips, or going out with a group. We were in a RV club and for her it was all about the social interactions. If you have activities in mind while RVing, you need to get her on board with those, or find something she likes to do. Otherwise it isn't going to work, or you'll be doing it alone.
