It sounds like you know what you need to do to cure yourself, then :-)
Rather than eating out at Restaurants as often, why not make a healthy picnic and go somewhere to eat it. Go for a walk together after. Find some physical activity to do for socializing - bowling can be fun. Leave alcohol for special occasions or meals only, but drink more mindfully - or not at all :-)
You can still enjoy yourselves - it can still be romantic - you can still avoid weight-gain.