<human>: After two years of what I thought was the time of our lives, he started saying we were "getting too much in a routine" and that "we're still young" and have a lot to see and experience. 
I said yes to this new kind-of "friends with benefits" arrangement, while publicly our relationship is over. I couldn't wrap my head around this fact, and I couldn't think of a thing I had done to wrong him.

I must not have been thinking of the consequences of an open relationship. At first,  I was fine with the idea - admittedly,  I'd somewhat enjoy the idea of no strings attached sex with other people.
However, seeing him constantly texting and messaging other guys on Grindr and such has made me increasingly jealous of this and envious of the attention he's getting (that I, for one, never quite had in the first place).

What should I do? Should I took the other way and try to control my emotions next to him? Should I come clean and talk to him to end it all? I don't want to have more meltdowns in front of him.

Give me a shortened version of the text
<bot>: My boyfriend of 2 years asked for an open relationship; I  accepted and I'm dying of jealously and regret.