Im so heartbroken I feel depressed what can I do?

I was with this girl for 10 years, I committed did everything I could to please her I tried to be a good partner and a loving partner for her everything was great

A few years ago she stopped calling babe, being affectionate loving and caring like the person i knew had evaporated she gotten very disrespectful and it was easy for her to argue everything I did felt wrong we stopped being intimate she started saying we felt like family not lovers

I still kept trying but I felt all I did was push her away she never wanted to go on dates or do anything romantic sex became non existent i felt like she hated me

3 weeks i found out she was on tinder so I told her I was going to pack my stuff and leave she did not care next day I pack my stuff and left I felt I was stopping her from being happy, I really miss her and I don't know why I was not happy and my needs was not being met, and now she's already dating a new guy after 10 years all it took was 3 weeks to find somone I'm so broken and confused I feel like I'm damaged i know I should not be feeling this way but I'm in soo much pain, how can I stop feeling this way stop being stupid.

Im so heartbroken I feel depressed what can I do?
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