Snoring is not just a matter of weight. I've been the same weight for years, but only started snoring quite recently. Gravity effects everything, including tissues of the throat. Plenty of people who have always been normal weight start snoring as they age.
Not all snoring is sleep apnea. A sleep study is a hassle but it would eliminate that and the sleep specialists might have suggestions ... although honestly, if you don't have apnea I'd try anything on this planet before a CPAP machine, my husband just can't get the hang of it (his non compliance has been the cause of numerous fights between us, in fact). If you do wind up needing a CPAP you MUST get a CPAP pillow (darned specialists won't tell you that but trust me, that lousy $60 pillow can make all the difference).
You could try one of those over the counter mouth guards ... or introduce your husband to these (I've been sleeping with them for nearly 20 years, actually can't sleep without them):