It's laughably common on the intarwebs for armchair psychologists to tell the person with the relationship issues to just "dump the jerk."
I'm of the opinion this isn't the end of the world and things can get better with some work and good communication. Maybe with the help of a counselor if the partners aren't able to do it on their own.
3 years is a pretty good run. There must be some good there.
Love withers under constraint; its very essence is liberty. It is compatible neither with envy, jealousy or fear. It is there most pure, perfect and unlimited when its votaries live in confidence, equality and unreserve. -- Shelley
Mags (poly, F, 61) loving miss pixi (poly, F, 39) since January 2009, living together since 2013
"Master," (mono, 34), miss pixi's Dom for 2 years