FWIW, I am mainly replying to the OP's last paragraph. I have not read all the other posts, just onewayward replies and thoughts.
Something in me is telling me that I am falling for this guy. And, perhaps, I haven’t been able to really hide that from him either (so hubby tells me), because he has started responding somewhat. Like, he’s started dropping by even when my daughter hasn’t come down to spend the weekend/holidays with us. And he’s been calling me often with some excuse or the other (must confess, I’ve called him a few times as well).
Just can’t figure how to handle this. But don’t want to let go either.
Are you just ENJOYING crush feelings? Could just enjoy them quietly then and not say anything to anyone. Nothing to handle. Just let it blow on through here and enjoy the scenery as it goes by.
Are you SUFFERING crush feelings? Could not see this guy or invite him over or call then. Give the feelings a chance to die down in "volume" so it's not causing you to suffer.
Are you thinking about STARTING something with this guy? I do not recommend getting involved with ANY of your daughter's current dating partners or exes. Ever. The world is big enough to not have to deal in "potentially messy people" like daughter's teacher, boss, minister, exBF, current lover, etc. Why make life difficult/awkward for your own kid? You? The potential person? It isn't like there's a people shortage where you live right? Where you don't HAVE anyone else around to date?
However if you want to pursue this? The simplest course of action is to just ask the daughter how SHE feels about it and if she will grant her blessing for you to date her EX. And wait to be sure it is EX!
Before even going there though, have you stopped to consider the "nutjob factor" risks?
And THERE'S the BIGGEST sticky wicket that I see. Even if daughter gives her enthusiastic, cheerful "Go mom!" blessing?
Maybe's he wants to fuck the set and then move on to the next set -- leaving chaos in his wake. There's people like that. Wanting to collect the set of cousins, sisters, mom/daughters, whatever. (I apologize for it being crass sounding-- I cannot remember the name of that particular fetish. )
Maybe he goes nutjob on all of you leaving chaos in his wake in a different way. Can you, daughter, and husband, and son deal with it and the aftermath? This isn't just being "outed" as a swinger or poly person and dealing with that.
If you and the guy become dating partners/lovers and he goes wacko? Then he's a guy who has been with you AND your daughter and can use that against you. Could just prevent it
by not even giving him that particular weapon to ding all your family with to begin with!
Could not put yourself in a spot where he can turn on you and go
- Said to you --- "Do THIS or ELSE I'll tell your daughter about us! I will tell EVERYONE about us!"
- Said to your DH, son, or daughter -- "I know something about Mom. It is THIS. And further, do THIS I will tell EVERYONE about us!"
Blackmail is not pretty. There's a skewed power exchange here... and it isn't the fun bedroom kind of power exchange of BDSM kinks.
It isn't just the power exchange shift between mother/daughter relationships when you are an adult and she's just crossing over into adult-ness to become your PEER and no longer your dependent. That's a sticky wicket all on its own as part of "general growing up."
THIS? This is the power exchange between the potential guy and you and your family members. What kind of power over you and your family could he misuse and cause you trouble in your lives? Social problems? Problems at work? Mental stress/strain problems? Maybe it's cool now. But how can you KNOW that he won't stab you in the back with it in the future? VERY risky because you just cannot know.
To me the emotional risks and price tag are much too great to pay -- both in relationship with the daughter and in relationship to the rest of your world if the guy goes nutjob on ya. Any dating partner could go nutter on ya, but it doesn't have to be magnified
by being a nutter who's been with both mom and daughter. That's a whole other level of hooha.
So I'm hoping you choose to just enjoy your crush thing quietly without telling anyone and let it fade naturally. Smaller cookies for you, but infinitely more digestible!
If you had to turn to a forum to wonder and think it out? That could be telling you something. In decision making, to me a solid joyful "YES!!" is a solid YES.
Any "maybe" or "no" is a NOT a joyful resounding "yes." So better to err on the side of caution and only
accept "YES" as "Yes." Anything less no matter how you slice it is just not a "yes."
Some choices in life is not "win or lose" but "which choice stinks least." In this case "not getting to date him" stinks less than "date him and risk all the hooha" to me.
Remember you are always free to choose things in your own life. You don't have to take on board stranger feedback. But remember you are not free of the consequences of your choices. Choose carefully.