Since my previous posts were deleted and I got a slap on the wrists for not giving advice and in the interests of not getting into further trouble I'll give you advice only about this "I don't want to go to Dunnes or anything but I'm not sure how to go about it, size and so on. Any ideas? Thanks." and not mention the other stuff, take it or leave it it's up to you.
I've no idea how heavy you are or how tall you are so all I can tell you is how sizes work and then you can work it out yourself. I'll do suspenders sizes first and tights next. Most women's clothes come in sizes like a size 12 or 14 etc whereas most men's clothes come in inches like a 34 inch waist or a 36 inch waist so Suspender belts come in women's sizes. To convert them from women sizes to men's sizes start at a women's size 12, a women's size 12 is a 32 inch waist so if your jeans are 32 inch waist then you are a size 12 WAIST in women's sizes (waist is in capitals there because a size 12 will work for a 32 inch waist but not necessarily your whole body so just because a size 12 suspender belt will fit doesn't mean a size 12 dress or blouse will, that probably doesn't apply to you but others reading this it might so I just want to make that clear). After that a size 14 is 34 inch waist, size 16 is a 36 inch waist, 18 is a 38 inch waist and so on, basically for every 2 sizes you go up in women's waist sizes you add 2 inches but most suspender belts are elastic anyway so you'll have an inch give room either way.
Tights are different, men don't really understand the categories so they come in 3 main categories, Tights, Holdups and Stockings. Tights are the ones that go all the way up kind of like leggings, Holdups are the ones go up to your thighs but have an elastic band at the top so stay held up without the need for suspender belts and stockings again go up to the thighs but have no elastic band so are held up with suspenders. they come in Extra Small, Small, Medium, Large, Extra large and XXL. These sizes are in relation to your height not your weight so Small would be about 5'5 in height, medium would be about 5'8, large would be about 6 foot but even though they are a stretchy material that size is based on a woman's body shape not a mans and a mans thigh is a lot thicker than a woman's of equal height so generally going up one size would probably be a better fit.
As for not going into Dunnes or anything there is no reason not to, for all anyone would know you are buying them for your wife and your only other options are buying them online which means you have to get them mailed to your house which I doubt you want or buying them in a sex shop where you will be ripped of for something you could easily buy in Dunnes or Penneys for one tenth of the price so the logical option is to just ignore the embarrassment and go for the cheaper option but that's up to you at the end of the day.