I don’t trust myself.

A few months ago me and my cousin got closer because of our unrequited love after some time of not talking due to our clashing personalities.
Now, about a year after I told her about my crush my cousin and him act really couple-y and are hardly denying anyrhing. I feel betrayed, unworthy and naive, even though he wasn’t even my boyfriend to begin with.
But the fact that we got closer makes me feel guilty to distance myself from her, while I don’t feel genuine because I fear I’m only with her so I can be with him.
I’m pathetic.
And lonely.