So, I have this boy that I've been interested in lately, and there's no question he's interested as well. We're in our second year of college, and last year he dated a girl who failed out of school at the end of the semester. From what I learned from his  friends there wasn't a change of them getting back together, but their relationship ended the last day of school, and he texts her every day. This past weekend she came to visit (luckily My family is visiting so I only saw her once), not just for him but just our friend group in general- and their interactions seems pretty harmless, but my paranoia is high because of PMS, and I've never dated anyone so far because of a huge fear of letting my guard down and trying to connect with someone without even knowing it's going to work out. With him, I actually feel like I can do that, which is great, but I guess my question is, should I be worried about the ex?