The MasterChef star explained that he has been "put off" by relationships, and that he definitely does not want to get married for a fourth time.
The 47-year-old broke up with wife Heidi in March after just over a year as a married couple.
"I couldn't marry again. No. I'm not even sure I could do a full-time girlfriend," he told The Sun.
"I've been put off romance a little bit. I'm now scared of relationships. I just don't want to fall in love with anyone. I just don't.
"I don't need a relationship. I have this great support network in Whitstable where I live. I've got my housekeeper and nanny, my PA and the home economist who helps me with all my recipes. All these three women are mates.
"They live near me and everything in my life is taken care of. I'm good at business but I'm not good with wives and girlfriends."
Wallace's ex-wife Heidi had continued as his PA after the split, and also looked after his two children. However, he explained that the break-up eventually made the arrangement difficult.
"She's moved out. I couldn't do it. It was constantly upsetting me," he said.
"We went to counselling but it just didn't work. We could have made it work if we had gone six months earlier but too much had gone on by then. I miss her. I was madly in love with her. The kids see her regularly."
Wallace added that his former partner does not want any money from their impending divorce.
He said: "Heidi doesn't want a thing. All those people suggesting Heidi was a gold-digger - it's so far from the truth."
Wallace will return with John Torode for a seventh series of Celebrity MasterChef tomorrow (August 13) at 6.30pm on BBC Two.