i think that is it OK is ambiguous. is it illegal, no. unethical not really. probably going to work out? iffy. though i just a met a guy who is about 39 who is dating a woman who is 52. they have been together for about 15 years. They are both professionally successful and have many hobbies in common and are very happy together. he is not particularly attractive and i'm guessing that probably neither she. so far so good. as someone who dated a guy 18 yo older than me when i was 19 for 3 years... in can say that at the time i would have married him or had his kid and in hindsight now after getting more life experience...i can see that this would have been a terrible mistake.