Ex gf already has a new boyfriend 5 months after the break up.

I (28M) literally havn’t been able to sleep bc of this. Just how easily replaceable I was. She’s (29F) literally in love with this new guy and he loves her too. I can’t stop comparing myself to this guy. He’s way more well off and ripped. We dated for 5 years and lived together for 4. Even owned the house together that’s still on the market to sell. All those memories and times she said she loved me forever, was such fcking bs. I feel super worthless and replaceable.

Any advice? Hurting fcking bad