I agree with shmerdloff, taking the high road. Sometimes, though, which one of several options is the 'high' one can present a bit of a dilemma.

Depending on your mojo, your energy, and on your personality, not to mention how likely your son is to side with one of you and not the other (IOW, you may lose your relationship with your son who is likely to be loyal to his wife, even if perforce), you might make things better in a lasting way if you make it clear to your DIL that you are averse to her treatment of you. Explain in unambiguous terms that you object to her 'put-downs', and have at least one recent example handy for illustration.

Do this when only you two are present. If it ever has to be repeated, THAT would be the time you insist that your son be present as well so that there is no misunderstanding of what happened and why, according to your objectives.

This might just be me, but I stand up for myself. I try hard to keep my temper in check (not always successfully, admittedly, but usually yes so as to be sure to be trudging on that high road).

The unofficial motto of the Royal Canadian Regiment, one of Canada's three infantry Regiments in the regular army, is, 'Never pass a fault.' That's sage advice for people who want to die happily and fulfilled.