No. He created a new branch reality by not returning from 1970 (when and where he returned the Tesseract).
There are 2 alternate universes that we know of. The one beginning in 1970, where Steve stayed - and the one beginning in 2012, when Loki took the Tesseract.
A 3rd is possible but unconfirmed. It's suggested that when Tony used the Nano Gauntlet, he was able to not only turn the 2014 Thanos army to dust, but he was also subsequently able to clip that branch reality ('cause Infinity Stones). It all depends on what they plan on doing with Gamora. If she's in GotG Vol. 3 - then there's definitely a 4th multiverse. If not, then Tony clipped that branch.