Between dizziness, fatigue, and the medications used to treat them, the answer is yes. You can discuss it with your doctor if you want, but I think it would be more important to be opened about it with your husband.
I don't have POTS, my daughter does, so i don't have personal experience, but I would think that POTS can cause sexual problems. It effects everything else. You may also be suffering from depression related to your illness and that effects sex drive. If you are on antidepressants, some will cause sexual dysfunction. I would definitely talk to the cardiologist about it. He may not know anything, but maybe he can refer you. It sounds like maybe you guys could use some couples therapy. Your illness is a huge strain on your partner also. It sounds like you need to communicate a little better and that's what counseling is for. Good luck. rbird