I would say yes... look at all the cheating that goes on in the world! Not an advocate for cheating, of course, because I've been cheated on and I know the pain and heartache it can cause. But I don't think you can put a limit on how many people you love. I love a huge number of family and friends, and I still feel love for a few of my ex's. But I love my husband unconditionally. I think it's possible to love one person (such as a spouse) and still fall for another. I think people in sexless marriages get caught up in such a scenario fairly often.
YES! I loved my wife but she would not take my cum in her mouth (she did once but then said she would never do it again) so I had many affairs, just to get what she would not give me. It didn't stop me loving her for 12 years and I did love her. If there is a sexual barrier in the bedroom, it will be a problem and one of U will look for the needed relief with a casual partner. which is so risky these days with the STD's out there.
I do believe people in love can cheat, because if you assume those in love would never cheat. You also have to assume those who aren't in love have the potential to cheat. Which is totally untrue. I'd never cheat on a guy, even if I fell out of love with him.
People in love can still be attracted to other people, but that doesn't necessarily mean they'll cheat. Only weak people cheat. If a person can't control their desires and emotions , then they are more likely to cheat, in a moment of weakness.