From what i've studied in the past Venus in 8th is a very lovely aspect because it gives your relationships a sweeter tone naturally, and your supposed to be luckier for marriage……
I don't know if that's so, but I have Venus in the eighth, and I've never married. One longterm relationship that was like a marriage, just not legally formalized, so I suppose you could count it as common law marriage... in any case, I've never really felt it mattered much to get married. I have a couple of other placements that might be contributing factors in that: Saturn in the seventh house, plus, my Venus is in Virgo, retrograde. Obviously, you feel it matters to get married, and you don't share those placements, either.
I can't say whether or not you ever will marry--for one thing, I'm much too amateur and inexperienced to even try to guess at a prediction like that, and for another, even fully qualified astrologers can't predict a person's choices--but as for your question of Venus determining your type of spouse, my understanding is that the seventh house and its ruler are the best predictors of that. With the seventh house cusp in Cancer, you probably need a partner who is nurturing and sensitive, and you're probably attracted to people like that. I also have the seventh house cusp in Cancer, and I certainly see that in me.
Moon in Taurus in the fourth (moon rules your seventh house) might add a desire for someone very stable, for a relationship with a solid base, a stable home, things like that. In contrast, my moon is in Sagittarius in the twelfth, and I've found that I really need an adventurous streak in a partner, as well as the nurturing qualities. The one longterm relationship I was in, we did a lot of traveling and moving around.
Your Venus may be in your eighth house, but it's at the cusp of the ninth. Many astrologers consider a planet within 5 degrees of a house cusp to be influencing the house it's approaching. With that kind of placement, you might have a strong desire for travel and learning, maybe teaching as well... and for people, including but not limited to a romantic partner, who can share that kind of experience with you.