Most Helpful Guy
Well I have always been single so this question doesn't apply to me. However to answer your question, it depends on another question, is the feeling of this boyfriend or girlfriend related to them being invited to party with them or not.
Mean if the boyfriend or girlfriend had invited them to the party with them but the refused the offer and stayed back home in that case they won't feel bad and left out, they won't feel neglected.
However if the boyfriend or girlfriend goes to the party and if they do so without inviting them or letting them know about it, then that would definitely be disrespectful and plus they will surely feel neglected, ignored and left you.0