<human>: I got close with a girl this year, we've known each other for about 5 months and have been developed a flirty and emotional relationship during the past month, and we seem to hit it off. We had a relaxing day of just walking our dogs and hanging out for a couple of hours at the park yesterday and she had to leave at around 6 because she had plans to "hang out with a friend." 

I know this is lingo for seeing some other guy she's probably interested in. And sure enough it was. Me being insecure I abused social media and concluded that these two have been messaging each other since last night. Even up until today.

I put the pieces together during our time together and I acted very quietly for the last 20 minutes of hanging out. I feel like I fucked up I should have said something.

I really want her but knowing the fact that she's seeing another guy (much more good looking than me), is fucking up my game big time. Right now I feel like just calling her and telling her how I feel although it would be a really bad idea. I know she can see whoever she wants, we aren't exclusive but I want to make her mine. 

Would it be unwise to talk to her about this next week? What should I say? I want to get over these insecure and desperate feelings and attract her.

Provide a brief overview of the text.
<bot>: girl I'm interested in is seeing a guy who is probably her ideal in looks. She also seems interested in me but I'm being insecure and am debating putting it all on the line in an act of desperation.