I think my boyfriend may be gay? should i confront him?

I have had some growing concerns that my boyfriend may be gay. At first it was that he was cheating on me or hiding something, but it now appears that he may be gay. He left his computer on after leaving in a hurry & after checking his emails found a user name & pword for an on-line dating service around the time we actually started dating 12 months ago. I went on-line expecting to find a string of females, however to my surprise his profile is clearly: man looking for a discrete relationship with another man. He has not been interested in for approximately 6 months, however initially the was very intense and regular. He has a lot of male friends (straight) and I regularly feel like he prioritises them over me. We have had regular arguments for the last 6 months as he has been distant and hasn't treated me like he wants a meaningful relationship...i think I now know why. I'm trying to think of possible explanations for his account but there are none.