Go You! for being so self aware & interested in your psychological/emotional/spiritual journey.
Stop giving yourself a hard time ... you're only 90 days sober for Pete's sake. Breathe. Relax. Be.
As far as your relationship is concerned ... yeah - as others have said ... it's not about her, it's about you. My experience of recovery (I'm co-dependent) has been that EVERYTHING is about me - not him. Just give it time & you'll figure it out. You're also assuming it's
your responsibility to make a decision about whether to continue/discontinue the relationship ... news flash ... the relationship is a dynamic between the 2 of you ... you're both playing out your intimacy needs/fears. Has it ever occurred to you to wonder
why such a wonderful young woman would take you back after all your cheating? Most women with healthy self esteem & boundaries would have shown you the door the first time. Ditto for the wanting to get married & have more kids. She wanted to marry & have kids with an addict? Really? I reckon that most relationships are pretty well balanced ... the partners are usually about as sick & or as healthy as each other. (That's just my own pet theory.)
As for sex ... well you said that when you get back together after a break up it's pretty good for a while, & also that you're more interested in her life & listening to her talk. Well, if you can do it for a while, you can do it. It's real. But you'll have to work on it if you want it to be a permanent feature in your relationship ... after you've been together for a while it takes a little more effort to keep the spark alive. There's nothing wrong with you or her ... it's just human nature, hard wired into us to ensure genetic diversity & the survival of the species. New sex partners are easy to be sexy with ... the hormones don't get drowned with issues & routine & hum drum. But if you want the benefits of a long term committed relationship you'll have to pay the price & work on it. Not very sexy I know, but possible. As you get a bit older you might be surprised at how sexy boring old things like genuine caring, sharing, compassion & familiarity become. But it usually takes a fair bit of skin off & a sharp drop in the "me Tarzan you Jane" type hormones before some of us can experience that. It did for me anyway
Good for you for posting & for sharing so honestly. That takes a lot of courage. My therapist keeps telling me that if I can maintain transparency (complete honesty), everything will be OK. So far, it's looking like he's right.
Congratulations on getting off the drugs. Fantastic, brave, life changing step. Now just have a bit of a rest before you try to take the next one. Kinda like a new baby giraffe ... you try & take too may too soon you're gonna end up in a tangled heap on the floor