Can Blood Pressure Meds w/ Beta Blockers Cause Drastic Personality changes?

My fiance recently started blood pressure medication w/ beta blockers, and it has caused the most drastic personality + mood changes in cud imagine! Not knowing wtf was wrong or why, I didn't figure it out until it was too late... She went from the most loving, caring + supportive partner ever, to a cold emotionally detached, hollow shell of herself.. She lost ALLLL feelings of love for me n broke off the engagement w/ no reason or conflict whatsoever... She states that she just doesn't want to be in a relationship now... Devoid of ANY emotion or feeling, and thinks a simple "sorry" is a cure all for her sudden drastic decisions to leave. I saw the ugliest side of a person I once loved more than ANYTHING, & still in shock that a blood pressure medication cud cause this much damage in such a short period of time... Has ANY1 experienced anything even close to this extreme shift n virtual 180° personality change, almost overnight? She wasnt on it more than a week b4 her 1st break up.. Only to reconcile a day later and have it all come crashing down 48 hours later....