Glad to see you are able to talk to your wife and that she's so supportive.
My advice in regards to the sexual stuff is be as open about it especially the insecurities. Communication is a powerful thing and and as you know it's uncomfortable to talk about things we're insecure about to the person we're most vulnerable with but it's the best way to put those fears at ease. They get to better understand you and reassure you.
(my username is appt for how I talk so I may not be very fluid in how I talk sorry!)
For example i was struggling to orgasm when with my partner regardless of if it was him manually, him using a toy or me using a toy... I just couldn't and I was getting really distraught about it. We talked in depth and worked together to find ways to help as it was to do with me feeling pressured to orgasm (he never pressured me, I was pressuring myself). He reassured me that I don't have to try to orgasm and to just enjoy the pleasure of being stimulated itself. We also decided to do a little fun shopping for a more suitable toy and got a wand. I orgasm regularly now but if I don't then I don't get upset anymore like I used to and just stop when I feel like I've enjoyed enough.
And the second example is that since me and my partner have been together I have had an insanely high sex drive which came as a shock to both my partner and me (first relationship for me and before him I only wanted to have solo time about once a month) as I want sex pretty much 24/7, after sex I'm right back to being horny within a few hours which is a bit of an issue if your partner is more of a once a day type... Cue me trying to stop myself dry humping him whenever he touched me. I by sheer force have been trying not to pressure him and I don't instigate sex but despite him saying he doesn't feel any pressure and trying to help me come up with ideas to get it more manageable (wand sessions, focusing on quality over quantity with sex and making me work out during it so I have less energy etc) I've been tying myself up in knots as feeling constantly frustrated to do anything with him as solo time isn't appealing unless I'm really desperate for release and then feeling like I'm wrong for being so horny and not having control over it.
After alot of googling I've found out the contraceptive I started taking before we started having sex actually increases sex drive and partner has agreed if it's upsetting me this much we will use none hormone based contraceptives so I can see if when my hormones are back to normal that my sex drive will change and what too (shall find out in next couple months as only stopped using the contraceptive two days ago).
Although partner has joked that if I have no sex drive at all he's going to rage as it will be roles reversed.
Just incase that is an issue we're prepared to talk to doctors about what we can do so it's not extremes in regards to my sex drive.
Not sure if it will help but you could have massage sessions where your wife fondles you either on your oenis or testicles whilst watching a movie, no actual masterbating or pretense to sex but just fondling like a massage. My partner finds it extremely relaxing and even falls asleep sometimes with it. He can tell me what feels nice, what feels great and what isn't so pleasant. It has nothing to do with erections, in fact if my partner gets an erection I just carry on massaging as if it's not changed because it doest mean we're going to do anything so there's no pressure to maintain an erection and no pressure on if the erection goes down.
It could help you get more comfortable with being handled with no pressure or expectations and is a nice peaceful bonding intimate moment which can be reciprocated back to your wife and see how she likes to be touched.
For me personally as issue mentioned previously I'm too easily stimulated at the moment but my breasts being massaged on their own isn't sexual to me at all and very very relaxing. Me and my partner take it in turns whilst watching TV or when in bed to relax before going to sleep or just because it feels nice.
Hope some of what I have said can help or maybe give you extra ideas to help you and your wife.