Potential threesome turned into cheating

For starters I am going to change some minor details around that would call me out, and leave some specific things unsaid.

Me and my girlfriend are both college age, and have been together since freshman year of high school. We’ve been through a lot together, including harsh trauma from family death and after her (already small) family ran out of funds to keep their house we moved in together.

We’re both trying to pay our way through school, and are making decent progress. However at my work I made friends with another girl who’s a decent bit older than the both of us. Me and this girl from work (TGFW from here on out) hit it off almost immediately, and being a man I didn’t see the signs that she was into me until later. After a couple of hangouts (and finding out that TGFW was into me), some involving my gf some not, a friend that is mutual between TGFW and I floated that TGFW would be interested in three way between me and my GF. I was enamored by the idea and went out of my way to plan hangouts to involve both of them to get the best chance of this happening.

Not that this will absolve me but my GF has had some intimacy problems, me and her have tried to talk them over and things improve at times but then return to how they were. However due to the length of our relationship and our closeness I already knew my GF was bi-sexual and willing to try a threesome, in my head I imagined that this scenario was entirely plausible.

As time had continued to move the tension between me and TGFW had already grown high, and in times where we were left alone we would both jump on the opportunity and make out and get touchy but only for very short periods, and it maybe happed 2-3 times. (Already bad I know) However after one hangout in particular hang out between all three of us, all of us being drunk, the ball finally started rolling.

My GF and TGFW had been off and on flirting the whole night and then my GF asked if she could kiss TGFW, I said yes and both parties involved did so. Whatever was there kind of fizzled out, and when I had second alone with my GF I asked if she was wanting to go through with a threesome now, she seemed unsure and even asked TGFW when she got back to us. TGFW said that she was down, but then once again the spark fizzled out and my GF went to bed.

Feeling extremely blue balled, I was upset but was sure there would be another time. When driving TGFW home, she came onto me and I folded. It turned into a nightlong endeavor, and here I am now. I felt extremely guilty for 2 or so days, then it kind of washed away. I got a text saying that TGFW got her period so we’re 99.9% good on that front, and with that weight off my shoulders I really only feel a small bit of guilt for what I did. A majority of my conscience is telling me that if a three way ends up working out that I would basically be absolved of my guilt, because all’s well that end’s well right?

If you want you can give me advice or directions in the comments, I’ll reply and possibly share some more info before I delete this post in a week or two.