I don't think that I'm not going to see my friend in person for a conversation on my girlfriends birthday
Are you going to have a long conversation with this about it later?
Not really, I just don't want him to ruin my girlfriends birthday. Also I can't stand him he is always making me feel bad about myself. It's honestly upsetting me.
If the conversation is very important, you shouldn't avoid it. You should be there for your friend.
Stop making me feel bad as I am going to talk to him. I just don't want him to try and ruin the party.
That's okay, you can always enjoy your party first and do all the talking later! But I believe you shouldn't delay such things, as conversation is super important to keeping friendships healthy. If you're honest, I believe he will be okay with what you have to say!