I keep catching my husband masturbating

Aggie
Okay ladies, so I need other opinions. 
I keep catching my husband masturbating in our home WHILE I'm in the house... like I think it'd be totally different if I was at work, or just not home. But it's the fact IM IN THE HOUSE AND HE DOESNT EVEN TRY!! ..And no it's not because I've denied him sex, he doesn't even try or ask. We're lucky to have sex 3 or 4 times a MONTH!! 
We just had our two year wedding anniversary (been together a total of 4) and I was downstairs uploading pictures from our weekend get away and he just disappears and I hear the shower, so I sneak up stairs to put on a sex outfit for him and be waiting for him when he got our, yet I walk upstairs to hear him masturbating in the shower instead of having sex (making love) to his wife on our ANNIVERSARY!! And this may be tmi but the night before we stayed in a hotel and I done things to him he's never ever seen me do and we had amazing sex (so I thought) just to come home the next day and he doesn't even try to touch me...
Is he just not attracted to me? 
Is he cheating? 
Is he not into females? 
I'm just so dumb founded and I'm so tired of feeling like I'm not good enough because my own HUSBAND doesn't even try to have sex with me. 
Like what am I doing wrong? 
I literally walk around in the house in a tvshirt and underwear. I'll take a shower and when I get out and have a towel wrapped around me, I'll drop it right in front of him and he doesn't even try to look at me. 
I'm just so confused and need advice on what to do.