Pleeeeese HELP!

I have been obsessed with my boyfriends masturbation habits for months with no one to talk with. It hurts me deeply that he needs to do this.it makes me feel totally inadequate, besides. I know he loves me, but I can't stop obsessing over it. I tried to talk to him, but he said it was none of my business really. He does it in my house that he moved into with me. He says he only loves me, and that it is only takes 3 minutes! *We have fantastic lovemaking. (everything works good), but when he masturbates I feel cheated and cheated opon. He says it's a natural instinct for a man and it shouldn't bother me. I would LOVE to make love more often and think if he didn't masturbate to images or porn, not sure, that he's cheating me out of more than once a week. He is very happy with my body, and my looks. he says he " just gets horny", so he does it..., well, why doesn't he make love to me then? Why can't he wait till I get home. I'm never gone for more than a couple hours! How would he feel if I moved into his house and I looked at and got off to sexy hot dripping men with giant penises and sexy muscular bodies while he was out. But why does he get horny when I'm gone and not when I'm there? I told him I'm not threatened by his masturbation, but why can't he do it while thinking of me? If I do occasionally, I think of him and hold no other visual of any man, only him. I'm stuck on this, and got so obsessed I place the lube in a way that I know he's used it, and he's so messy about( probably because he's so focused on his pleasure he leaves it running down the side)Of course I get angry and cannot be close to him the entire day, but since he told me it was none of my business, I have dreaded talking to him again. I realized that I probably caused him to have more intense desires now that he doesn't consider it cheating, but in his mind! he's actually probably more stimulated now that it's more naughty. I found out about your brain on porn and am at least compassionate that he could be addicted and how the brain works with dopamine and Coolidge effect and am more relieved he actually has a physiological addiction and not that he doesn't truly love me, but I don't feel trust and wonder if he ever goes to strip clubs during the day since he has his own business and has time while he's away.
So one day I got angry enough that I decided to find the best looking biggest dicks I could find ( yes,passive aggression) to masturbate to get even, but it's doesn't make me feel better. then I decided to leave my iPad open to these guys hoping he will open it and find them to help him see how it feels, but he's still engaging in it regularly.*
I need some one or many to please be compassionate and not critical to help me to realize something. Please don't tell me to grow some skin, or that it's not about me, etc. etc., and how pathetic I am and insecure. Everything I found when I googled said all those things to other women who felt the same.
If its so frickin normal why doesnt he pull out his iPad while we're watching tv and go at it with me right there? Why in my deepest heart do I feel sooo bad about it?*
I think that and how he scans around looking at women when we're out and how he used to look for movies with sexually explicit scenes make me feel I can't trust him. He satisfies me in all other ways. Hes attentive, romantic, loving, affectionate, very complmentary, and so on.
It is ruining my ability to give my whole heart and stay connected 100%. I am a fiercly loyal Scorpio women and need to feel the same loyalty!*
Is there anyone who can offer some advice, ENCOURAGEMENT especially to help me . I love him very much, but I feel his habit is tearing our relationship apart. He is the first man to love me like I've always dreamed of, but that one thing im obsessed about.
Thank you in advance!