Hullo and welcome!
Do a tag search on NRE (New Relationship Energy). It's something everyone starting out on poly will have to face at some point, and you are not the only one having hard time dealing with it. Check out Indigo's (TruckerPete's husband) posts, especially his blog. There are probably others in similar situations on this forum but he popped into my mind first.
Me: bi female in my twenties