Relationships are obviously different for everyone. Being married is definitely a lot different than being in a casual relationship, so I can't fully understand what you are going/what you went through. I can only share what I've personally experienced thus far.
If there's no trust, then there's no relationship, really. I hardly ever call or text my boyfriend when we're apart. Only when something important comes up (or if there's like a really funny video/meme that I know he'd love lol). Otherwise, I almost never know what he's doing and who he's with. I realize he has his own life, his own interests and a lot of the time that probably doesn't involve me.
My boyfriend doesn't party anymore, drink/smoke/etc, but he still hangs out with party people. His best friends are like those guys who constantly plan the best party ever. And a lot of the time Pedro is still there because he's the "sober driver" so he's probably around promiscuous ladies a lot but it's whatever. I trust him and he's not really like that. (Also keep in mind that some of his friends have moved a few cities away and he still keeps in contact with them so sometimes he's even out of the city for days/a week.) We have a really chill relationship. It's been over a whole year already and we're nowhere near that "i love you" stage. He does his own thing and I do mine. Best relationship I've had so far.
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