Friends or boyfriend..............?

I know what the obvious awnser in this is, but please read. I'm 15, just finishing up the 9th grade and have been dating this boy for a month. He lives in the city and I get to see him once a week or so. Yesterday my school went on a trip to a massive public park, right by his house. I invited him because I really wanted him to meet my friends. Both my friends and him were friendly with each other but there was tension. My friend took me aside and said she really didn't like him, and that none of my other friends did either. I didn't want to ruin their day so I took him away and we hung alone. We did go back every hour or so and talked and such, because I also wanted to hang with my friends. At the end of the day, after he left, me friends cornered me and started bashing me, calling him the worst person they have ever met, without reasoning. Normally I would say "okay, I'll just break up with him, they see something I don't" but I really like him, and I feel like they aren't being too fair. We are really geeky where as he is an outdoors guy. If they gave reasons then I'd definatly think everything over, but they didn't. They are also very angry that I hung with him instead of them, but I did because I wanted them to have a fun day and because I never get to see him. What should I do? Just ahve 2 seperate lives? One with him and one with them and not cross them over?