Hi Bells, So, yeah, I'm in a relationship with a guy who has 3 other partners and an infant and, 16 months later, I'm at a crossroads about where I want to be. However, my recommendation would still be to give it a try. I fell in love and had some great experiences with my SO. I hope to have more with him still, maybe as partners, maybe just as friends. You know that you want this guy in your life in some way, this is definately one way.
The NRE you both have will probably mask some issues, like time management, but isn't that the case with all new relationships?
I do recommend getting any preconceived ideas and expectations out on the table as soon as possible. What do you each think the relationship will look like? How much communication are you each comfortable with? (Hopefully, a lot. You mentioned he likes to text.) I've found that that conversation avoids some frustrations and awkward adjustments at the beginning. Of course, you want the relationship to grow organically and things can and will change.
Have you met his girlfriends? One of the things that really recommended my partner was that I was comfortable with his OSOs. They seemed thoughtful and sane. It gave me more confidence in the whole situation. Good luck!