He was meeting women in Yahoo Chat rooms. He admitted to talking to them about his/her sexual needs, exchanging picture and so forth.
This is called an "emotional affair". An "emotional affair" is the stage of an affair before sexual intercourse is involved. It is not a separate type of affair... merely a precursor to intercourse.
It is infidelity, though not, to split hairs, "adultery".
My wife's affair was an emotional affair. The most it ever led to was a kiss on the cheek and the other man (OM) squeezing her buttocks.
It was still absolutely devastating to my marriage, and I recorded the two of them calmly discussing leaving their respective spouses to raise a combined six children together.
An EA is still an Affair. Period. Recovery is identical.
That said, there's a very good chance at least one of these online romances turned physical. Do not believe your husband's protestations of innocence. The VAST majority of the time, so-called "emotional affairs" are actually physical affairs that the wayward spouse is trying to down-play to avoid consequences.
Your situation is not special or unique, and neither is your husband's behavior. It's absolutely typical.
Please buy a copy of "Surviving An Affair", by Dr. Willard Harley and Jennifer Harley Chalmers. It will outline your roadmap to recovery after your husband's infidelity. Once you've done so -- you can buy it on Kindle for PC or Mac for just $10 from amazon.com, and have it about five minutes from now -- come back here for some information not contained in the book regarding exposing this series of online affairs for what they are, and helping your husband stop his behavior and return as a full partner in the marriage.