Speak for yourself, I remember a recent democrat president saying "If you like your health care plan, you'll be able to keep your health care plan, period"; This turned out to be false, didn't it?
This is actually a pretty interesting topic, if you care about the facts and details and aren't just parroting right-wing talking points.
Obama’s pledge that ‘no one will take away’ your health plan
The oversimplified short version is that health care is complicated and Obama made some campaign stump claims that really needed nuance. The ACA did have provisions for grandfathered plans but it also required them to meet rules around coverage changes and price increases or they lose that status. Some states also have laws that conflicted with grandfathered plans that prevent people from keeping them.
Frankly, most of the plans that were no longer valid under the ACA were shitty plans anyway and only provided the illusion of medical insurance. They didn't cover preventive care, had ridiculous maximum coverage limits, lacked coverage for serious illnesses, or didn't allow for expensive treatments. Basically they covered a runny noses and stubbed toes but not cancer or diabetes -- the exact kinds of things that drive people to medical bankruptcy.