I don't think I can post a link, but just google "the hero's spouse" and you'll find the links.
The site also mentions that spouses will often realize that the OW isn't right for them, but they don't want to fail at another relationship and it's easier to stay in that one than to try again with the S, at least at that moment.
Even though my H has told me that she's using him, he keeps taking her back and has told me that he wants to "give her a chance" and try to make it work.
I don't remember in your sitch how long your H has been with OW, but usually it's all fun and games. They don't have to worry about bills, chores, or any grown up stuff. They don't have kids together and she doesn't worry about him spending too much money because it's not her money.
M36 XH34 M-5 T7 4/11 H confused 5/11 ILYB 6/11 OW discovered 7/11 I move out, OW over 5/12-OW2,done->new EA, but H wont file 9/12 H "best bf ever" to EA/OW3 3/13 H/OW break up H files 4/13 D 6/18/13