When I was still shy and embarassed about my body and such, I also got really defensive about this subject.
I also said that I never had done it and never would do it, that it was wrong, and gross etc. Which of course were all lies.
But, now that I have matured and grown, I am not ashamed anymore of something so natural and normal.
You cannot depend on anyone else to keep you 100% satisfied. It isn't fair to you or your partner. You cannot be around each other 24/7 and even if you were you probably wouldn't want to have sex with each other! You would be too frustrated from being with them so much.
Also, sometimes we just need to please ourselves quickly. Just get it done. And sex is then not what we really want.
So, don't be embarassed anymore!