Dear Ibby, Is it okay to date my mom's ex-boyfriend? I'm 23 and he's ... old.
You're so grounded.
Assuming he's your mom's ex-boyfriend, not the current inspiration for her "It's Complicated" status on Facebook, then I'd say date the age-mediated rheumatoid arthritis right out of him. Does it matter that he's old? Hell no. That means he's been with decades worth of women, and probably knows his way around the female anatomy like Siri knows her way around my heart (you're such a tease, Siri! Giggle giggle). Sure, he may have a little bit of Erectile Dysfunction every now and then,and periodically need you to replace the tennis balls on his walker, but there's pills for that. In fact, I applaud you for taking him off the market; that's one less maniacal old dude at a strip club getting in the way of my tit view.
And does it matter that he's your mom's ex? That part depends on your relationship with your old lady. Are you best friends, or do you harbor a not-so-secret resentment for each other stemming from the fact that your accidental birth was the reason she had to stop drinking vodka for five months? Yeah, that's why you can't talk good.
If your relationship is such that dating her ex would hurt her feelings and damage your mother-daughter bond, then leave that geezer be. Dudes are a dime-a-dozen, but you only have one mom (or two, if you're Wanda Syke's spawn). It would suck to risk harming the person who is closest to you, and I'm sure there's another rapidly aging octogenarian you can get your hands on that hasn't also porked your mom.
However, if your mom is a modified witch and your relationship consists of you guys dating each other's ex's to spite one another, or, if you never talk, then call that dude up and let him put it in you. Dating people's ex's is fine; everyone is someone's ex at some point, and people don't own their ex's like they think they do. If your mom qualifies as "people" instead of "mother that I love," the congratulations because you have a shiny, less-than-new boyfriend.
Either way, talk to the misses first about it and see what she thinks. She may have something to say like, "Oh, Larry? He doesn't know a clit from a cardboard box," which, at the very least, will give you some valuable information you can use to leverage cash out of him. Or, she might be like, "I gave you life, and this is how you repay me?" which is a great sign that you should frequent a different nursing home for potential dates. Most likely, your relationship with you mom lies somewhere in between "most important person in my life" and "who's that?" so just make sure to weigh the risk of hurting her feelings with the reward of being with someone who fought in the Civil War.