The simple answer is yes to both.
Why and how did you and your husband arrive at opening up your marriage?
Him finding someone might ease your guilt but could add many other negative complications that could easily spiral out of control....hard to put the genie back in the bottle.
Have you told your husband you've lost that lovin/lusty feeling for him?...could prompt him to step up his game....and or look elsewhere for that romantic component. Assuming that honest communication was the cornerstone agreement upon taking this journey together seems unfair to withhold such an important change in feelings or attitude. Honesty is the best policy in this situation, saves time and the confusion and mixed words or signals.