Final answer:
Mr. Bingley's interactions with Miss Darcy are not detailed, but he remains consistently polite and affable with others. Strong indications of his enduring love for Jane Bennet are his prompt proposal to her upon his return.
Step-by-step explanation:
Mr. Bingley's behavior towards Miss Darcy is not explicitly detailed in Jane Austen's 'Pride and Prejudice', but it can be inferred that he behaves with the same polite and friendly demeanor that he does with most characters in the novel. There is substantial evidence that Mr. Bingley is still in love with Jane Bennet, not with Miss Darcy. For instance, upon his return to Longbourn, after having been persuaded by Mr. Darcy to leave Netherfield for a time, he immediately seeks out Jane's company and shortly thereafter proposes to her, proving that his affections have been constant.