Was Ryan the father?

I have seen this posted a lot before posting tbh but I was trying to see anything after the airport scene discussed but it’s always right after the phone call between Ryan and Theresa that’s discussed. I also know that the show creator said the kid wasn’t Ryan’s but then why the heck do they look more like Ryan than Theresa and Eddie? Why have the whole story line of how it was obvious Ryan was the father and Theresa just wanted him to go back to his life in Newport because she felt it was the right decision? This is one of the only plot points that truly annoy me and can’t be explained away for “good tv” imo. Thoughts?