We're commanded as believers to rejoice with those who rejoice.The point of Christian dating is to find a suitable spouse.
If there is strife, again the issue is sin (James 4:1-2).
What may be needed, should this man ask you out on a date and should that date lead to a relationship that in turn leads to a falling out with your friend, is help learning how to walk biblically in friendship.
Attraction is an emotional response to someone you like.
Through the course of your life, you may find yourself attracted to any number of men, many of whom will have had former girlfriends.
But as you can see, in most situations, to someone is not reason enough to pursue a relationship with him.
In most cases, it's a reminder that we need to continually submit our thoughts to Christ's lordship, taking every thought captive and making it obedient (2 Corinthians 10:5). And so we pray, "And lead us not into temptation, but deliver us from evil" (Matthew ).
That should come as good news to her, even though it may remind her of her own disappointment that she's still waiting for a similarly good match.
(That's another area for prayer and patience, and the ability to trust in God's sovereign plan.) It's no reason to begrudge him, though.
(This is true of every man you consider dating, not just this one.) If your friend and this man conducted themselves biblically, however, with all purity (1 Timothy 5:2) even as they tried to determine if they were a good match for one another, and decided in the end that they weren't, there's no reason they should feel tied to one another, or have any sense of ownership or influence over future relationships.
If your friend cares for this man and wants what's best for him — and if they had a godly breakup — she should rejoice if the two of you decide to date and possibly marry.
If you said you thought she was “The One” and your “Soul Mate,” I might reconsider, but she would have to hold that sort of potential.