First off, we can't interpret "love" in the mushy Valentine's-Day sitcom sense we imagine today. "Love" here is a lot more significant and difficult than that.
Love in the Old Testament sense is not divorced from actions. Loving actions don't spring from love; they are an inherent aspect of love. As wax eagle points out in the comments above, sexual intercourse was the central way that a man loved a woman. There were other ways, such as giving gifts, favouring her sons, etc.
It seems to me that in this case it does not mean sexual intercourse. Let's look at the whole of chapter 3:
The Lord said to me again, ‘Go, love a woman who has a lover and is an adulteress, just as the Lord loves the people of Israel, though they turn to other gods and love raisin cakes.’ So I bought her for fifteen shekels of silver and a homer of barley and a measure of wine. And I said to her, ‘You must remain as mine for many days; you shall not play the whore, you shall not have intercourse with a man, nor I with you.’ For the Israelites shall remain many days without king or prince, without sacrifice or pillar, without ephod or teraphim. Afterwards the Israelites shall return and seek the Lord their God, and David their king; they shall come in awe to the Lord and to his goodness in the latter days. (Hosea 3, NRSV)
It seems to me that what Hosea did was a kind of love that didn't involve sex, but was about his redeeming her (i.e. buying her back) and dwelling with her and keeping her from playing the whore.
Now, let's look at the book of Hosea and why this passage exists. The book was written as a denunciation of the cultic practices of the Northern Kingdom. It is an extended metaphor, where the prophet Hosea represents God and Gomer his wife represents the faithless people of Israel, who had been "playing the whore" by worshipping foreign gods. (Whether Hosea and Gomer were real people is entirely beside the point.)
Hosea's loving action in buying back Gomer represents God's loving action in buying back Israel despite her unfaithfulness. So Hosea's purer, less physical way of loving his wife is a promise of a time when Israel and God would once again live together in a pure form of love.