Is it gay to do what I do?

Ok. I am 16 years old and I was wondering if this was ok. From around 12 years old, I remembering finding a couple of my moms vibrators and dildos hidden in her room. I knew that after my dad got back from iraq, she didn't have a reason to use them anymore, and i got curious, and i knew she wouldn't notice them being gone... After a bit of self training and stretching... I was soon able to fit a full 7 inch dildo with 6 inch girth all the way into my anus... I LOVE the Feeling!!! It gives me great orgasms and I feel like being fulfilled with something greater!! I love it hard and deep, and I'm getting Way hard just thinking about it. But I wanted to know if I'm still straight. I currently have a girlfriend who is 17 and i find her irresistibly attractive. I love her C-cup sized breasts and her nice, firm, butt. I sometimes finger her and she'll rub me off too, and i love her, I plan to marry her, have kids, etc. etc. but I don't want to suddenly turn out gay one day... especially since her last boyfriend turned gay on her... I don't ever think about guys sexually and i'm not attracted to them. I only think of women sexually, and i'm always turned on by the woman i love... but either way, I just wanted to know if i can do this and still be straight. Thanks to those who can be of any help.Is it gay to do what I do?
Straight.