Twin flames are often (not always, but often) in other relationships when they meet because that level of readiness and evolution tends to attract other people.
Your twin bond is constant, energies linking every second even in separation. That telepathic connection doesn’t shut off just because they’re with someone else, so you pick up stuff you don’t want: dreams, emotional waves, flashes, even physical anxiety. All the same channel.
Karmics are temporary by design. They settle karma, teach lessons, burn hot then fizzle. Totally different energy from twins; full of friction and compromise, never sustainable.
Hang in there. This sucks, but it passes.