Serious relationship virgin

So I have never in my very short life been in a serious relationship... I mean I'm not complaining but I have this guy who treats me right and wants to actually date who has been hurt before might I add... but then again who hasn't been hurt? Anyways I've never been in a monogamous relationship and I was wondering if it's supposed to be hard? We've been talking for a couple months and he wants to be serious and I want to be too. I'm afraid that I'll cave or that i'll mess things up and do something wrong. My old "exes" have been trying to bait me and so far I've been doing well at ignoring them, avoiding them and telling them that I didn't want to do that anymore because i finally met someone who i actually want to try with and I'll be damned if i let them fuck that up for me. I need help. It should be easy right? Because i keep finding personal obstacles and I'm starting to doubt im worth all the trouble.