Welcome to the forum!
I think you are feeling the pressure that society, culture, religion, and even the law, press upon us to be monogamous !
I'd suggest buying a book immediately - "the Ethical slut". - its about how to conduct relationships with honesty and integrity, while not necessarily monogamously.
You are on the right track to be considering other people's feelings. I think we are all attracted to many people at the same time , and thats fine - I think you are looking for a way to deal with these feelings without hurting people - GOOD!!
Male M, struggling noob.