Anyone in a functional relationship does things to please another - I think its a matter of whether / how strongly they feel against it. I have no desire to massage my wife's feet but she likes it and it's not a big deal for me, so why not? This is obviously much bigger than that and requires more consideration but its the same principal. If you feel strongly against it, then sure, don't proceed. If you just have no personal desire for it or are uncertain but not strongly against it and know it means a lot to your husband, then it is perhaps worth considering.
Also, at some point, I think almost all of us have experiences where we were reluctant to try something but we're pushed into it by circumstances or another person and discover we actually enjoyed it. Sometimes its impossible to understand why you might like something until you've given it a shot. There are many wives on this site who have talked about a similar beginning, not thinking they wanted it and being coaxed into it by a husband only to find they really enjoy it. Then again, you may and wives who don't like their first probably don't come post here, so hard to know what the ratio is there. I guess you need to determine whether it is something you feel you might seriously regret for whatever reason or whether its something you could try and, if you don't like it, just move on and never do it again with no harm.
It is something that might help stimulate your sex drive though and thereby potentially improve your marriage.
FWIW my wife is also insecure about her body even though she looks great for her age and far more attractive than her friends. There is nothing I can do as her husband though to change that since she assumes I love her, so of course I'd say she's attractive. The reality though is most of us men are not expecting a supermodel, nor could we get with one if we tried. A lot men are just happy to have some new pussy and will appreciate you for your better qualities and overlook your imperfections. I can also tell you, attitude and sensuality do a lot more for me than just physical appearance. I've dated some very attractive women who were boring and my wife, while good looking, is certainly not the hottest woman I've been with - yet I've never been more attracted to anyone, because of her sensuality.