I became a vegetarian (lacto-ovo) myself on April 10th 2008. And that after three consecutive years eating 6 days a week at McDo for 3 times a day. I supersized before the film was there.
Your husband needs to clarify the reason why he became a vegetarian in the first place. If it is weightloss only than he will not succeed. He can still eat meat and than with the proper exercise he will loose weight.
The main problem for me was that I could not tell what to eat in stead of meat. So it became bread and cheese, for supper lettuce/tomatoes/cheese and that was it. I grew bigger, because after eating my dinner I started to eat crackers and cookies.
I went to a good dietician and she and I made up an overview what to eat in which combinations. She checked my body on vitamins and minerals stats. It seemed I had built up (during my meat eating years) an deficit on minerals and vitamins. I am taking now supplements and I feeling muc better.
Weightloss since starting a vegetarian dieet AND regular exercise AND supplements is 6.0 kilo in two months. The trick for me is that my metabolism seems to be changing. If I do not eat in time, than I start getting real hungry and a bit insecure. That is something I never have experienced before.
Good luck!
PS. It does not hurt to minimize meat intake for yourself and cook one meal for both.
PS2: Some soya milk has sugar added. You think you are doing the right thing, while instead you are damaging yourself. So allways read the ingredients.
PS3: It is not you that should find out what to eat, if your husband is serious about his new lifestyle he should try to find out for himself what to eat.