My man only wants to have sex once a week with me I think it's abnormal, he say's its totally normal?

First of all, find out how he feels about sex. Ask him how he feels and don't fall for answers about what he thinks about sex. If he grew up with any exposure to what is taught in some churches, or elsewhere, he might be right, for where he is coming from. Trouble is, he isn't there anymore.
Healthy sex lives are negotiated with some give and take from both sides. You might want to read 1Corinthians 7 (focus on verses 1-5) and the Song of Solomon. Many churches have ignored the part about authority over each other's bodies in marriage and the sexual language in Song of Solomon. Sex is neither dirty or only for procreation. If that were the case, women would not have the only mammary glands in nature that are designed for pleasure, rather than efficient feeding of the young.
Depending on the person, daily, weekly, monthly or even yearly sex might be adequate. I like to make love more frequently, as a way of adding physical pleasure to my wife's life. My focus is on her pleasure when I am making love to her, not my self. Sex is something that can be done for selfish reasons, in which case, it is only sex. As an investment in the other person, it becomes love making, because you are performing the act in order to make them feel the pleasure, not pain, of your love. With love making, how much pleasure my wife receives has a major impact on how much I enjoy it. With sex, how much pleasure your partner has is not a major consideration.

I'm 39, and still single, and looking, but not for a sex partner, even I could not deal with sex 3 times a week, I just have too many responsibilities. all I want is someone who understands how rough life is, and just unwind at the end of the day with a little dinner and some TV. save the sex for the weekend. this way you don't have to worry about waking up late in the morning.

Dump him. He's turning down sex who does that? He has to be able to compromise with you. How many times do you want it per week? Is it excessive do you want it 3 times a week? Yes he may not be a teenager wanting it so eagerly but he's still a guy. I don't think he has a normal sex drive or maybe he doesn't view sex as a high priority. There are some men out there who don't even like sex and if so then its very limited. Your saying the sex is ok it's not great or fantastic but it's not shitty. Do you guys do the same thing or do you mix it up a bit?
Sex should not be the bases of one's relationship but if there is no midpoint then I suggest to find someone with a similar sex drive