I am a Belgian citizen (quite white...) and married my quite black wife 6 years ago when we were both working in Johannesburg. There's a 17 year age gap, the same as with my Zimbabwean parents in law (Mkua, Kezi). I sat on the reeds mat and paid lobola (10 cows + 1 penalty goat for living together before getting married!).
We are running a preschool in Bulawayo. My wife is director and I occupy myself with accounting. It's always quite funny to see the reaction of prospective parents when they first meet with me in the office and then my wife walks in subsequently wearing a school uniform (T-Shirt and flat shoes) and introducing herself as the director! It also confuses the hell out of salespeople ;-)
My experience after 1.5 year in Gaborone, Botswana, 3.5 year in Johannesburg, South Africa and now 5 years in Bulawayo, Zimbabwe is that Zimbabwe by far the most relaxed country when it comes to interracial couples. Probably the only ones who show any concerns are the white hidden minority. Oh, and I just need to be aware that veggies at the market are at least double in price when I show up ;-)