Who is 'Pulchritudo'?

Whilst re-reading The Private Papers of William Wilberforce, I came upon a letter Pitt wrote to Wilberforce from Brighthelmstone (known as Brighton in modern times) dated Wednesday, August 6, 1783. Now, there’s nothing particularly noteworthy about the letter apart from a name, or rather a nickname, of a person who I’ve never seen in any other source. In the letter, Pitt talks about his upcoming trip to Rheims in France with Eliot and Wilberforce, and then goes on to talk about how he is enjoying his time by the sea.

Here’s the relevant part: “The lounge here [in Brighthelmstone] is excellent, principally owing to our keeping very much to ourselves - that is Pulchritudo, Steele, Pretyman, and myself…and the better part of love as well as valor is discretion…” (Wilberforce, 1897: 5-6). If this was an unknown love interest, Pitt would have had to have been extremely discreet, which he always was, in order to keep it a secret. Am I missing something here? Who is ‘Pulchritudo’? I have yet to find another reference to this person, or certainly the nickname, anywhere else. Of course, I could be overlooking something obvious, and if I am, do let me know.

Also, is this a typo in the printed text? ‘Pulchritudo’ may not be a word in the English language, but pulchritude most certainly is - and it means Beauty. So who is this unnamed beauty?

Again, in the same letter Pitt refers to the value of discretion in matters of love, so perhaps he chose not to write the person's name in the letter? All of this is mere speculation, but it’s intriguing nonetheless as no one seems to have picked up on the obvious before (unless I’ve missed something huge). These are my personal ruminations, but it’s definitely something to ponder.

Reference:

Wilberforce, A.M. (ed.) (1897) The Private Papers of William Wilberforce. London: T.F. Unwin, pp. 5-6.