Strange symptoms both partners having racing heart, and weakness?

This is something that's been ongoing for awhile, first I got it for months. I can't exert myself without my heart jumping from 70 sitting to 96 walking in seconds. I can go days like this than I get energy zapped right out of me. I stay in bed for days just weak, with pressure rushing in my head and slight headache, and heart hurting. I have had ekg, ultra sound of heart, wore heart monitor and cbc. Last week my husbands heart starting racing and he was getting short of breath and complained of weakness, We can't figure out whats going on, we both have been tested for hep a,b,c. Doctors put us on beta blockers, It's not helping me at all, and he is still having some weakness as well with moderate, heart racing. I keep thinking we both have some type of bug. What could be making both of us have these symptoms. Any hints? could this be something infectious?