1. Our Tony and Steve are in the outs, no established relationship
2. A Tony from an alternate universe past (40s?) ends up in their timeline
3. Alternate Tony is more cocky, self assured, confident
4. Reed is consulted to verify Alternate Tony
5. Our Tony was sent to Alternate Tony's timeline where he meets that Steve (pre-serum)
6. Our Tony and Alternate Steve falls in love
7. Our Steve with Alternate Tony goes to get our Tony, but Alternate Steve wants him to stay
8. I THINK this was after the Civil War. I think.
9. Ends up being Steve/Tony
10. I think there's a sequel on our Alternates.
See? Lots of little details but may not be particularly helpful. Hence listing otherwise confusing.