I don't know how "serious" it was, per se, but 17 year old me was pretty crushed. I had dated a guy for 3 years (so all through high school, we were those guys). It was semi-long distance - he lived in a town on the other side of the bay, about 30-40 miles away. We did a lot of dumb shit to keep that relationship going, and sometimes it worked. But towards the end it was nothing but rocks and teenage angst. The last straw was finding out about all the other girls, and all the lies.

That relationship thoroughly fucked me up for a good 6 years or so until I was old enough to really own my problems and start working through them.

Turns out, this dude was a real piece of work. In hindsight, I'm glad my Dad fucked with him.

• He only started dating me because my other friend wasn't interested and he wanted to stay close to her.
• He dated a neighbor that lived across the street who had the exact same interests, personality, and style as I did for about 10 months (while WE were dating too).
• He tried to long distance date another chick he'd met at a summer camp, again, while we were dating. And would regularly meet up with her/take her out whenever she was in the area. Something he rarely did for me. When he realized she wasn't interested, he suddenly showed up in my life again full force - I had no idea.
• His lovely friends KNEW about neighbor chick, and never said a word to me about it the entire time. FFS dudes we played guitar hero together!
• He spent the majority of our relationship openly and shamelessly pining for one of his other friends. I caught them having an obviously intimate conversation on New Year's day at mini-golf. When I immediately left he chased me down to try convincing me I was crazy (thanks, dick).

It was literally one of the most ridiculously over the top and stupid relationships I've ever been in. And I fell for this guy HARD. It was my first big relationship and I had no idea how shitty people could be. He did a really good job of gas lighting and making ME feel like I was the paranoid, naggy girlfriend.

About a year after the fact, he finally got the girl he was pining for. But not before he swelled to a massive 400 pounds (on a 5'5 frame). He "accidentally" sent me a picture of her giving him a bj (gross). When I showed up for a reunion of sorts at his friends place another year down the road, she spent the entire time hugging him and giving me the stink eye. He looked and smelled like literal shit. I was like no problem lady, you can keep your trash.

I only started to really heal when a) I realized he was a loser with some serious problems. and b) I found out that he was still living in the same cat infested piss soaked shit hole pawning xbox parts on craigslist. Sweet justice.

That was long and cathartic, thanks reddit.