I can't climax anymore

I'm a 21 y/o gay male, and I've been sexually active since I was 16. I've enjoyed oral sex in the past, never penetrative. Recently (over the past year), the only time I can climax is when I self-service. Other people just can't get me off as god as I can myself, and I don't seem to enjoy the intimacy of sex anymore (not even kissing, or romance in general). The last few sexual partners I've had, I was dating, but I wasn't very interested (if I am being honest). Although this hasn't been a problem in the past, could it be this? any other males/females similar?

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