Should I keep in contact with my daughter in law as she is always putt

She's got the problem, not you. Set your highest standard for the relationship. This gives her a bright line to see and reach for. She will make it one day, or not, but you will not have compromised your standards (which you would not be happy about) and have gone into the muck with her.
This also allows your son's household to deal with one unhappy person instead of two.
In short, a great judge I knew lived by, "Take the high road."

I always had a problem with a few family members and friends and I would always take it, I was a very forgiving person but it I be lying if I said that it didn’t bother me. I changed a lot mentally and physically over six years ago when I had to deal with cancer, I also learned very quickly how little they cared about me, it was a painful transition and still hurts to think about it but it’s a work in progress.

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.

It really isn't hard for me to deal with people who don't like me. For the most part, I just don't care. But I have learned to avoid those people as much as possible and not respond in kind. Life is too short to let people like that bother you. I would really only deal with my son when I can and deal with DIL when I have to, and at the very minimum possible. However, I think I would always be open to her if she ever decided to act differently, in a good way. Just maybe your not acting in-kind might soften her up.

@frouke
You finf out what things really have been about. That's a gift. The disbelief is cognitive dissonance.
You can look around for other current sitations that you suspect are not what they seem
Listen Frank Wildhorn's It's a fač̣ade. Or even Harpur Valley PTA🤣

Take it to the Alley:

You don't give any details. Is there a reason you need to contact her instead of your son? Are there grandchildren? You don't mention the alternative. I can't provide an opinion without some context/content to your question.

@zorro12345 what a beautiful piece of music, such depth. It’s a call to all to extend ourselves to those in need, here in the present not to wait for the afterlife.

My sister-in-law is like that. I like to read Carolyn Hax’s advice column (syndicated). She suggests the Gray Rock technique (Google it), short disinterested, but polite, answers. So I say, “Wow”, or “That’s harsh”, or “I’m sorry you feel that way.” Keeps the temperature down, doesn’t cause escalation, signals you’re not going to protest or defend or justify. Your DIL knows what she’s doing, refuse to play her game.

@grandmira

May you live today with your hands open. May you discover that the more freely you give, the more freely you receive. May the generosity of God flow through you as naturally as water seeking its level.