Help. In hetero relationship but thinking of same sex

Hi. I am in a committed, loving relationship, but lately I can't stop fantasizing about doing something with another guy. I don't think my gf would be okay with it, so how do I stop thinking about it? It's all I want to do and it's driving me crazy lol

 

You don't stop thinking about it. If you do it, you will want more.
The best you can do is figure out if ruining your current relationship is worth it. Having sex with someone else - even if it is the same sex - is still cheating and lying to your current relationship, it will weigh on your mind.

You could maybe try to find a Bromance, another guy who also wants to keep it quite. But often there is an emotional attachment that develops. Jealousies always screw things up. The fantasy of a "hook up" often does not relate to the reality of it.

 

Like TwoBiFour said, don't try to stop thinking about it. Fantasizing is normal for everyone.
Is your girlfriend aware that you are bi? Maybe you could start there?