Sounds like you really need to have a heart to heart talk with your wife. Are you giving her any reasons to suspect anything hanky panky is going on during your dive trips? Are you diving with a female dive buddy? If no to both...then continue reading:
Tell your wife how important diving is to you. Ask her to come along to offer surface support. Put her in charge of some of the logistics and give her some responsibility to manage on her own...she may like that. Like shopping for picnic supplies, or picking the next dive spot (maybe one around an area that she wants to visit also).
And here’s the real kicker...do something things with her that she likes that you may not. If you love her and she loves you, you both need to work something out. Scuba diving is supposed to be a stress reliever, not cause marital problems. Good luck man!