You have reached a stage in Life where most of your responsibilities have been fulfilled. You are also successfully running a Business which I am sure gives you lots of joy. Unfortunately since your husband is not with you, there must be times when your hormones are raging and you feel the urgent need for sex.
Many women have a heightened sexual urge when they reach their mid-ages and with time on your hands, it is natural that you want sex and are willing to experiment to get it. Since you already had a sex with a man half your age, the encounter must have been very satisfying with you being in charge. You must have already realized that a young man (unmarried) is full of energy and wanting to please a woman in bed, he would be willing to do your bidding.
You talk about having a boyfriend. Why have a boyfriend when you can have casual sex without any strings attached. The problem with a boyfriend is that the affair soon gets messy with demands made from both sides. If it is strictly sex, then you will not have to worry about either of you falling in love with each other and creating problems for everyone.
The idea of having many partners to have sex with may be appealing to you, but there are problems of jealousy (the men will be) and the biggest problem is ensuring that they do not have any STDs. Remember that each boyfriend can also have other sex partners, leading to fear of HIV etc. You must at all times, insist on use of condoms.
Have you given thought, how you will handle the situation, when your husband and son come to know about your indiscriminate sex? Divorce can happen. Are you prepared for that?