This is an important issue. At 49 you are ‘subfertile,’ but not infertile. You also can’t rely on rhythm, as there is no rhythm!
Barrier methods--condoms or a diaphragm--can work well, although they take some anticipation and planning. (If you're in a new relationship, you might also consider the protection condoms provide against STIs, too.) If you choose that route, intravaginal spermicides in combination with the barrier will give you some additional coverage. The birth control pill, which is approved for use until age 55 or menopause, can still be an option. If you did well on it in the past, you would likely do well on it again; a careful health history would help make sure you are a good candidate. Now pills can be given in such a way that you menstruate much less often, or not at all. And one more option: There is an IUD on the market that lasts 5 years--likely to get you to menopause.
What you choose depends on your health history and your personal preferences. I'm glad you're both enjoying your sexuality again and paying attention to this issue!