Hi Sugar Blue,
Lima beans, be they small or large (and the big ones are sometimes called "butter beans"), are relatively easy on the tummy. So are all the different varieties of lentils. You might start with these, and then branch out to cranberry, pinto, pink and Navy beans. Take it slow and easy, you've got lots of delicious food to look forward to!
Keep in mind that your innards gradually get used to what you eat frequently -- so if yours are delicate, and you want to eat beans on a regular basis, you should add small amounts to each day's diet, allowing your tummy some time to get used to them.
Also: If you soak your dry beans in very soft water (add baking soda if your local water is hard), the cooked beans will not only be very rich, gooey, soft and luscious, but also will be less gas-inducing.
Finally, if you have not yet heard about it, there is an over-the-counter "nutri-ceutical" called Bean-O (or maybe just Beano) which claims to reduce or eliminate gas discomfort for folks with delicate stomachs. Being the BeanLady and all, I have never tried it (beans haven't given me gas since the first Reagan administration. . . oy, am I old or what?). But I gather it really helps people like yourself, who have sensitive innards and want to enjoy the culinary delight of beans. Good luck!